Retail Inventory Glossary: 50+ Terms Every Retail Manager Should Know
Comprehensive alphabetical reference covering every major term in retail stock management, from ABC analysis to write-offs. Each definition includes context and links to our in-depth guides where applicable.
A
ABC Analysis
Inventory classification method that divides products into three categories: A items (top 20% of SKUs, ~80% of revenue), B items (next 30%, ~15% of revenue), and C items (bottom 50%, ~5% of revenue). Used to prioritise management attention, cycle counting frequency, and safety stock levels.
Read more →Auto-Replenishment
System that automatically generates purchase orders when inventory levels hit predefined reorder points. Eliminates manual ordering for routine items and reduces stockout risk from human error or delayed reordering.
Read more →B
Backorder
An order placed for an item that is currently out of stock. The customer agrees to wait for the item to be restocked. Backorder rates are a key metric for measuring inventory health.
Read more →Batch Tracking
Recording and tracing inventory by production batch or lot number. Critical for recalls, expiry management, and quality control. Common in food, pharmaceuticals, and cosmetics.
C
Carrying Cost
The total cost of holding inventory, including storage, insurance, depreciation, obsolescence, opportunity cost, and handling. Typically 20-30% of inventory value per year.
Read more →Cycle Count
Counting a subset of inventory on a rotating schedule rather than shutting down for a full physical count. A-items might be counted weekly, B-items monthly, and C-items quarterly.
D
Dead Stock
Inventory that has not sold within a defined period (typically 6-12 months) and is unlikely to sell at regular price. Dead stock consumes carrying cost while generating zero revenue. Must be marked down, liquidated, or written off.
Read more →Demand Forecasting
Using historical sales data, statistical models, and external signals to predict future customer demand. Ranges from simple moving averages to AI/ML models that incorporate weather, events, and promotions.
Read more →Drop Shipping
Fulfilment method where the retailer does not stock the product. Instead, the manufacturer or wholesaler ships directly to the customer when an order is placed. Lower inventory risk but less control over fulfilment quality.
Read more →E
EAS (Electronic Article Surveillance)
Anti-theft tags and detection systems placed on merchandise. Tags trigger an alarm at exit gates if not deactivated at the POS. Common types: acousto-magnetic (AM), radio frequency (RF), and RFID-based.
Read more →Economic Order Quantity (EOQ)
The optimal order quantity that minimises total inventory cost (ordering cost + carrying cost). Formula: EOQ = sqrt(2 x Annual Demand x Order Cost / Carrying Cost per Unit).
Read more →Endless Aisle
Retail strategy enabling in-store customers to browse and purchase from the full product catalogue, including items not physically stocked in that location. Enabled through kiosks, tablets, or mobile apps.
Read more →F
FIFO (First In, First Out)
Inventory rotation method where the oldest stock is sold or displayed before newer stock. Critical for perishable goods. Implemented during shelf stocking by placing new items behind existing items.
Read more →Fill Rate
The percentage of customer orders fulfilled from available stock without backorders or stockouts. A fill rate of 95% means 95 out of 100 orders were completely fulfilled immediately.
Read more →G
GMROI (Gross Margin Return on Investment)
Measures profit earned for each dollar invested in inventory. Formula: GMROI = Gross Margin % x Inventory Turnover Ratio. A GMROI of 2.0 means $2 gross margin per $1 of inventory investment.
Read more →I
Inventory Days on Hand
The average number of days inventory is held before being sold. Formula: 365 / Inventory Turnover Ratio. Lower DOH generally indicates more efficient inventory management.
Read more →Inventory Shrinkage
Loss of inventory from theft (external and internal), administrative errors, vendor fraud, and unknown causes. US retail shrinkage totalled $90 billion in 2025.
Read more →Inventory Turnover
How many times a retailer sells through their average inventory in a given period. Formula: COGS / Average Inventory Value. Higher turnover generally means more efficient inventory management.
Read more →J
Just-in-Time (JIT)
Inventory strategy that receives goods only as they are needed for sale, minimising inventory holding. Requires reliable suppliers and accurate demand forecasting. Reduces carrying costs but increases stockout risk.
Read more →L
Lead Time
The time between placing a purchase order and receiving the inventory. Includes supplier processing time, manufacturing (if applicable), and shipping. Directly affects safety stock requirements.
LIFO (Last In, First Out)
Inventory accounting method where the most recently purchased items are recorded as sold first. Used for tax purposes in some jurisdictions. Not to be confused with physical stock rotation (which should always be FIFO).
M
Markdown
A reduction in the selling price of merchandise, typically to clear slow-moving inventory. Planned markdowns are budgeted; unplanned markdowns indicate forecasting or buying errors.
Min-Max Inventory
Simple replenishment method: when stock hits the minimum level, order enough to reach the maximum level. Easy to implement but does not account for demand variability or lead time changes.
O
Obsolescence
When inventory loses value due to technology changes, fashion shifts, or regulatory updates. A significant component of carrying cost, especially in electronics (rapid model cycles) and fashion (seasonal trends).
Read more →OMS (Order Management System)
Software that manages orders across all channels and routes them to the optimal fulfilment point. Essential for endless aisle, ship-from-store, and omnichannel retail operations.
Read more →Open-to-Buy
A planning tool that calculates how much new inventory a retailer can purchase within a budget period. OTB = Planned Sales + Planned Markdowns + Planned End Inventory - Current Inventory.
ORC (Organised Retail Crime)
Professional theft operations that steal merchandise for resale rather than personal use. Targets high-value, easy-to-resell items. Growing problem with increasing violence against staff.
Read more →P
Perpetual Inventory System
Continuous tracking of inventory levels through real-time recording of all transactions (sales, receipts, returns, adjustments). The alternative is periodic inventory, which only updates levels during physical counts.
Read more →Phantom Inventory
Stock that exists in the inventory system but not physically on the shelf. Caused by shrinkage, scanning errors, or misplaced items. Prevents automatic reordering and causes customer-facing stockouts.
Read more →Pick-to-Light
Warehouse picking system where lights on shelving indicate which items to pick and in what quantity. Increases picking speed by 30-50% compared to paper-based methods.
Planogram
A visual diagram specifying exactly where each product should be placed on retail shelves. Defines shelf position, number of facings, and product orientation. Created by category managers or merchandising teams.
Read more →POS (Point of Sale)
The system where retail transactions are completed. Modern POS systems combine payment processing with inventory tracking, customer management, and reporting.
Read more →Purchase Order (PO)
A formal document sent to a supplier specifying the items, quantities, and agreed prices for an order. POs create a legal commitment and provide a paper trail for receiving verification.
R
Reorder Point (ROP)
The inventory level at which a new purchase order should be placed. Formula: ROP = (Average Daily Sales x Lead Time) + Safety Stock. Setting accurate ROPs prevents both stockouts and overstocking.
Read more →RFID (Radio Frequency Identification)
Technology using radio waves to automatically identify tagged items. Enables real-time inventory visibility, faster stocktakes (90% time reduction), and improved theft detection. Increasingly adopted in fashion and grocery.
S
Safety Stock
Extra inventory held as a buffer against demand variability and supply disruptions. Formula: Safety Stock = Z-score x Std Dev of Lead Time Demand. Higher service level targets require more safety stock.
Read more →Sell-Through Rate
The percentage of received inventory that was sold within a given period. Formula: Units Sold / Units Received x 100. A sell-through of 80% in 30 days is strong for most retail categories.
SKU (Stock Keeping Unit)
A unique identifier for each distinct product variant (size, colour, style). A single shirt style in 5 colours and 4 sizes creates 20 SKUs. SKU count is a key factor in inventory system selection.
Slotting
The process of assigning products to specific warehouse or shelf locations based on pick frequency, size, weight, and other factors. Optimal slotting reduces picking time and improves stocking efficiency.
Read more →Stockout
When a product is not available for sale because inventory has been depleted. Costs the global retail industry $1.2 trillion annually in lost sales. The average stockout lasts 35 days.
Read more →T
Turnover Ratio
See Inventory Turnover. The number of times inventory is sold and replaced in a period. Higher is generally better, but excessively high turnover can indicate understocking.
Read more →U
UPC (Universal Product Code)
The standard barcode system used in retail. The 12-digit code uniquely identifies a product. Scanned at POS for pricing and at receiving for inventory tracking.
V
Vendor Managed Inventory (VMI)
Arrangement where the supplier manages the retailer's inventory levels based on agreed targets and POS data. Common for beverages, snacks, and other high-frequency categories.
Read more →W
Warehouse Management System (WMS)
Software that manages warehouse operations: receiving, putaway, picking, packing, and shipping. Essential for retailers with dedicated warehouse or distribution centre operations.
Read more →Write-Off
Removing inventory from the books when it has no remaining value. Triggers include damage beyond repair, expiry, obsolescence, or confirmed theft. Write-offs are recorded as a loss against gross margin.