ERP Inventory Glossary: 41 Terms Explained for Manufacturers

FEFO (First Expiry, First Out)

FEFO is an inventory rotation method that sequences picks and production consumption by expiration date rather than receipt date. The lot with the nearest expiration date is consumed first, regardless of when it was received. FEFO is required for food, pharmaceutical, and cannabis manufacturers with limited shelf life inventory.

In ERP, FEFO enforcement requires expiration dates captured at receiving and pick logic that directs operators to the earliest expiring available lot, not the most conveniently located one.

FIFO (First In First Out)

FIFO sequences picks and production consumption by receipt date, so the oldest received inventory moves first. It is also a costing method: when inventory is sold, the cost of the earliest received lot posts to cost of goods sold first. FIFO and FEFO align only when expiration dates match receipt order.

In ERP, FIFO costing requires each received lot to carry its actual receipt cost, and cost of goods sold posts at the oldest available lot's cost when units are sold or consumed.

FEFO vs FIFO: Key Difference

FIFO sequences inventory by receipt date. FEFO sequences inventory by expiration date. The two produce the same pick order only when lots expire in the order they were received. When a supplier ships a fresher batch before an older one, which happens regularly, FIFO ships the wrong lot. For any product with a shelf life, FEFO is the operationally correct method.

Standard Cost

Standard cost is a predetermined cost assigned to a product or component based on expected material, labor, and overhead under normal production conditions. It is set during budget planning and held fixed for a period, typically one year, regardless of actual costs incurred. The gap between standard and actual cost is a cost variance.

In ERP, every receipt, production completion, and cost of goods sold posting uses the standard cost, with variances posted to variance accounts for analysis.

Average Cost (Moving Average)

Average cost recalculates an item's unit cost each time new inventory is received, blending existing cost with the new receipt's cost. The new average equals total on-hand value divided by total on-hand quantity after each receipt.

Average costing is common in mid-market ERP because it avoids the lot-level tracking FIFO or FEFO required, though it is less precise where lot-specific cost matters for margin analysis.

Cost Variance

A cost variance is the gap between an item's standard cost and its actual production cost. Material variance compares standard to actual material cost. Labor variance compares standard to actual labor hours. Overhead variance compares applied overhead to actual overhead incurred.

Variances are posted to general ledger variance accounts when a production order closes, and recurring variances usually signal that standard costs need updating or production has drifted from plan.

Related: Landed Cost

Landed cost is the total cost of acquiring inventory, including purchase price plus freight, customs duties, insurance, port fees, and domestic cartage to the receiving location. It is the true per-unit acquisition cost.

Without a landed cost module, the ERP books inventory at purchase price alone. A landed cost module allocates freight and duty into unit cost, producing accurate margin data on imported inventory.

Perpetual Inventory

Perpetual inventory continuously updates records in real time with every transaction: receipt, pick, production consumption, adjustment, and shipment. Balances are current at any moment without a physical count, unlike periodic inventory, which updates only when a count occurs.

Perpetual inventory in ERP depends on every physical movement being recorded as it happens; scan-based execution supports it, while manual entry introduces lag.

Periodic Inventory

Periodic inventory updates records only when a physical count is conducted, typically at period end. Between counts, cost of goods sold is estimated, and balances are not real time, making it less accurate for operational decisions but less resource intensive.

Most manufacturing ERPs default to perpetual inventory, with periodic retained in legacy systems or for low-value bulk categories where perpetual tracking overhead is not justified.

Safety Stock

Safety stock is the buffer quantity kept above expected demand to protect against supply or demand uncertainty, such as supplier delays, demand spikes, or quality holds that remove planned inventory from supply.

Safety stock sets the minimum level in ERP reorder rules. When on-hand inventory approaches it, the ERP triggers a replenishment signal, and safety stock quantities are excluded from available to promise.

Reorder Point

The reorder point is the inventory level that triggers a replenishment order to avoid a stockout before the next delivery arrives. It equals average daily demand multiplied by supplier lead time, plus safety stock.

ERP reorder rules generate a purchase or production order suggestion once on-hand inventory reaches the reorder point. AI demand forecasting can update reorder points dynamically as consumption patterns shift.

Cycle Count

A cycle count audits a portion of inventory on a rotating schedule, so every location is counted over a defined period without halting operations for a full physical inventory. ABC classification sets count frequency, with the fast-moving A item being counted most often.

ERP cycle count modules generate count tasks by ABC class, assign teams, and post adjustments for discrepancies, replacing annual physical inventories where perpetual records are accurate.

ABC Analysis

ABC analysis classifies items by consumption value or velocity. A items are roughly 70 to 80 percent of inventory value across a small share of SKUs, B items are 15 to 25 percent of value, and C items make up the remainder.

ERP inventory modules run ABC analysis automatically from transaction history, feeding cycle count scheduling, minimum stock settings, and slow mover identification for write-down review.

Three-Way Match

A three-way match is a procurement control requiring a purchase order, a goods receipt, and a supplier invoice to align before payment is approved. The purchase order sets the agreed price and quantity, the goods receipt confirms actual delivery, and the invoice states what is billed.

ERP three-way match automates the comparison at invoice entry. Mismatches, such as an invoice price above the PO price, generate a hold that routes to purchasing or receiving before the payment run.

Purchase Order (PO)

A purchase order is a formal document a buyer issues to a supplier specifying items, quantities, prices, and delivery terms. An approved PO creates a financial commitment in the ERP and is the system of record for the transaction.

ERP POs track receipt status by line, support partial receipts, and remain open until fully received or manually closed. Open PO value feeds the commitment report for cash flow planning.

Goods Receipt

A goods receipt is the ERP transaction recording inventory's physical arrival from a supplier, transfer, or production completion. It updates on-hand inventory, relieves the open purchase or production order, and creates the payables accrual.

Scan-based goods receipts create the inventory transaction in real time at the receiving dock, eliminating the lag of manual entry.

Lead Time

Lead time is the elapsed time from a process's start to completion. In procurement it runs from PO issuance to goods receipt; in manufacturing it runs from production order release to finished goods completion. Lead time drives reorder point and scheduling calculations.

ERP vendor records store expected lead times used in MRP, and actual performance can be measured against them for supplier scorecards.

Bill of Materials (BOM)

A BOM is a structured list of components, subassemblies, and raw materials required to build a finished product, with quantities and units of measure for each. Multi-level BOMs nest subassemblies built from lower-level components.

The BOM drives MRP: the ERP explodes it to determine how much of each component the production plan requires. BOM accuracy is the single most important input to reliable planning.

MRP (Material Requirements Planning)

MRP is the ERP calculation that determines what to order and when, based on the production schedule, BOM structure, current inventory, and supplier lead times. It generates planned purchase orders and planned production orders.

MRP typically runs daily or weekly and produces suggestions planners review and confirm. Its accuracy depends on BOM accuracy, inventory accuracy, and lead time data quality.

Work Order (Production Order)

A work order authorizes and records the manufacture of a specific product and quantity. It carries the BOM, routing, planned cost, actual material and labor consumption, and the finished goods receipt, posting actual cost when closed.

Open work orders represent work in process. WIP value equals materials issued to open orders plus labor and overhead accumulated but not yet posted to finished goods.

Available to Promise (ATP)

ATP is the uncommitted portion of on-hand inventory and scheduled production that can be promised to new orders. The formula is on-hand inventory plus scheduled receipts from purchase and production orders, minus firm order commitments, calculated period by period.

ATP gives customer service a confirmed delivery date, and its accuracy depends on inventory, open production, and sales order data staying current in the ERP.

Work in Process (WIP)

WIP is the value of inventory started through production but not yet completed as a finished good, including raw material cost issued to open orders plus accumulated labor and overhead.

ERP WIP valuation sums actual costs on all open production orders. Closing an order relieves WIP and debits finished goods inventory.

Routing

A routing is the sequential list of operations required to produce an item, defining the work center, operation, and standard setup and run time for each step. Routings drive scheduling, labor cost capture, and capacity planning.

MRP uses routing lead times to calculate manufacturing lead time, and work orders generate individual operations from the routing for shop floor tracking.

Lot Traceability

Lot traceability is the ability to track a production lot's history forward, to which customers received it, and backward, to which raw material lots contributed to it. It is required under FSMA 204, AS9100, pharmaceutical cGMP, and cannabis state regulations.

ERP lot traceability requires every movement, from receiving through production, packing, and shipping, to record the lot number so a full chain of custody can be reconstructed.

Serial Number Tracking

Serial number tracking assigns a unique identifier to each individual unit, tracing which operations, components, inspections, and customer it passed through. It is required for aerospace, medical device, and defense manufacturers.

Serial numbers differ from lot numbers, as a lot covers units produced together, while a serial number identifies one unit, and a single lot can contain multiple serialized units.

Goods Issue

A goods issue is the ERP transaction recording inventory leaving stock, whether to a production order as material consumption, to a shipment as a cost of goods sold posting, or to an internal transfer. It reduces on-hand inventory and posts the related entry.

Production issues credit inventory and debit WIP; shipping issues relieve finished goods and post cost of goods sold at shipment.

Allocation vs. Reservation

An allocation is a soft claim, where the ERP sets aside a quantity for an order without tagging a specific unit. A reservation is harder, tagging a specific lot, serial number, or bin for an order and removing it from the pick pool.

Allocations reduce available-to-promise quantity; reservations reduce availability and remove specific inventory from picking, so the two affect ATP differently.

Inventory Write-Down

An inventory write-down reduces carrying value to net realizable value when that value falls below cost, required under GAAP when inventory is slow-moving, obsolete, or nearing expiry such that a full-price sale is unlikely.

The ERP entry debits write-down expense and credits inventory, updating the lot or item's carrying value so the balance sheet reflects recoverable value.

Landed Cost Allocation

Landed cost allocation distributes freight, duties, insurance, and handling across the items in a shipment, adding these costs to each item's unit cost. Methods include by weight, by value, or by quantity, depending on how the cost is spread.

Landed cost modules post the allocated cost at receipt, updating unit cost to reflect true acquisition cost. Without it, the margin on imported items is overstated.

Drop Ship

Drop shipping is a fulfillment method where the supplier ships directly to the customer, bypassing the distributor's warehouse. In ERP it requires a customer sales order, a supplier purchase order, and a shipment confirmation that closes both without an inventory receipt.

Drop ship transactions post cost of goods sold and revenue at supplier shipment confirmation, and open drop ship orders must be closed together to avoid period-end reconciliation gaps.

Consignment Inventory

Consignment inventory is held by one party but owned by another until a triggering event such as sale or consumption. Supplier consignment keeps stock supplier-owned at a distributor's warehouse until sold; distributor consignment keeps stock distributor-owned at a customer site until consumed.

The ERP must track ownership separately from physical location, since ownership determines balance sheet treatment regardless of where the inventory sits.

Accounts Payable Accrual

An accounts payable accrual records a liability to pay a supplier when goods are received, before the invoice arrives. It debits inventory or expense and credits accrued payables, then clears once the invoice matches the PO and goods receipt.

The accrual keeps the balance sheet current on received goods ahead of invoicing, satisfying GAAP accrual basis requirements, and the three-way match clears it when invoices process.

Backflush

Backflushing automatically issues components from inventory when a production order or operation completes, instead of requiring individual picks to be scanned and recorded, deducting components based on BOM quantity at completion.

Backflushing cuts data entry but assumes BOM accuracy and weakens lot traceability, since it records standard BOM consumption rather than the lots actually picked. Regulated manufacturers such as food and pharmaceutical companies typically avoid it for tracked components.

Variance Account

A variance account is a general ledger account capturing the gap between standard and actual cost in a standard cost ERP. Purchase price variance compares PO price to standard cost at receipt; production variance compares standard to actual cost at work order close.

Variance accounts accumulate through the period and are reviewed at close, with large or recurring variances signaling outdated standards or production inefficiency.

Demand Forecast

A demand forecast projects future customer demand, typically built from historical sales, seasonality, and known upcoming orders or promotions. Forecasts feed MRP and reorder point calculations so planning reflects expected demand, not just current orders.

ERP and connected AI forecasting tools generate forecasts at the item and location level, updating as new sales history arrives, which reduces both stockouts and excess safety stock.

Phantom Assembly

A phantom assembly is a subassembly on a BOM that is never stocked or built as a standalone item, existing only to organize components logically. The ERP explodes through it directly to the underlying components during MRP and production.

Phantom assemblies let planners group related components without creating unnecessary work orders for an intermediate item that is always consumed immediately.

Catch Weight

Catch-weight products have an actual unit weight that varies from a nominal weight, common in meat, seafood, cheese, and produce. They are priced by actual weight but tracked using both a standard unit and the variable actual weight.

ERP systems built for catch weight need dual unit of measure tracking, capturing both units at each transaction for invoicing and inventory valuation.

Pick List

A pick list is the document instructing a warehouse operator which items, quantities, and locations to retrieve for a sales order or work order, typically sequenced by location to minimize travel.

ERP-generated pick lists can apply FEFO or FIFO logic automatically, directing the picker to the correct lot rather than leaving selection to judgment.

Wave Picking

Wave picking groups multiple orders into a single batch released to pickers together, based on criteria such as shipping deadline, carrier cutoff, or picking zone, to optimize travel and throughput during peak periods.

ERP and warehouse systems that support wave picking release picks in scheduled batches rather than one order at a time, coordinating pick, pack, and ship around common cutoffs.

KDE (Key Data Element)

A key data element is information required to be captured and retained at a critical tracking event under FDA FSMA Rule 204. Receiving CTE KDEs includes the traceability lot code, product description, quantity, location, receipt date, and supplier name and location, producible to the FDA within 24 hours of request.

ERP systems must capture KDEs at each event, including receiving, production, and shipping, in a structured format enabling forward and backward trace queries.

CTE (Critical Tracking Event)

A critical tracking event is a defined point in the food supply chain where the FDA requires KDEs to be captured under FSMA Rule 204: receiving, when food arrives; transforming, when it is produced or processed; and shipping, when it leaves for a customer or distribution point.

Every CTE must generate a structured KDE record in the ERP at the moment it happens, with scan events at receiving, production completion, and shipping confirmation as the typical triggers.

TLC (Traceability Lot Code)

A Traceability Lot Code is the identifier assigned to a specific quantity of food at a Critical Tracking Event under FSMA Rule 204, linking the lot to all KDE records at subsequent CTEs to form the chain of custody from raw material to finished goods.

TLCs are typically generated from or aligned with the ERP lot number at receiving, and every later production and shipping transaction must reference it to maintain the full traceability chain.