The rack-room vocabulary, defined properly.

A warehouse full of other people's goods: storage and fulfilment run as a paid service for client brands, rather than a company minding its own stock room. Everything distinctive about 3PL operations follows from that one fact — many owners on one floor, each with their own inventory, rules and rate card, and every move on the floor belonging on somebody's invoice. If everything in your building belongs to your own company, you don't run a 3PL warehouse; you run a warehouse, and a standard WMS is the right tool.

The record of what actually arrived, counted at the dock — as opposed to what the ASN promised or the client's email implied. The GRN anchors everything downstream: inventory accuracy, the start date of storage billing, batch and expiry capture for anyone who'll need FEFO later, and the evidence that ends month-end disputes. Sloppy receiving is where 3PL margins go to die; the GRN is the discipline that stops it.

The client's advance notice of an inbound shipment: what's coming, how much, and when. In a well-run flow the GRN is reconciled against the ASN and variances are flagged at the door, while the truck is still there to argue with. In real life plenty of inbounds arrive with no ASN discipline at all — which is exactly why the count at the dock, not the promise in the email, is the record that stands.

The move from the receiving dock to a storage location, with the location recorded. Directed putaway assigns each pallet or carton a real bin code, so 'where is my stock' becomes a lookup instead of a walk of the floor. In a multi-client facility, putaway also carries the segregation: one client's goods get an address that belongs to them, and never drift into another client's count.

The address of one physical slot in the warehouse — rack, bay, level, position. Location codes are what turn a floor into a database: every putaway writes an address, every pick reads one, and every cycle count verifies one. A warehouse without location codes still has inventory; it just exists mostly as a rumour.

Two ways to pick more than one order per trip through the racks. Batch picking groups the lines of several orders into a single pass; wave picking releases orders to the floor in scheduled waves — by carrier cut-off, by zone, by client. Both exist because walking is the enemy: travel time can run up to 50% of picking activity, so how you group orders decides how much of the day is spent commuting between racks instead of picking from them.

The sequenced route a picker walks through a wave — bins ordered so the trip is one clean pass rather than a pinball tour of the racks. With travel time eating up to half of picking activity, path sequencing is one of the few places where software saves labour minutes directly, order after order, all day.

Two ways of checking that the system matches the shelf. A stock take counts everything at once, usually with the floor stopped — thorough, disruptive, occasional. A cycle count counts a rotating slice (a bin, a zone, a client) continuously, without stopping operations. A 3PL needs both: rolling cycle counts to keep accuracy verified week to week, and the full stock take for when a client or an auditor wants the whole floor proven at once. In a multi-client warehouse, variances are flagged per client — because someone specific owns every discrepancy.

First-In-First-Out issues the oldest-received stock first; First-Expiry-First-Out issues the stock that expires soonest first. For anything with a shelf life — food, pharma, cosmetics — FEFO is the rule that keeps expired goods off the outbound dock. The catch: FEFO only works if batch and expiry were captured at the GRN. You cannot pick by an expiry date the warehouse never recorded, and no amount of software at the pick face fixes a blind receiving dock.

The work beyond store-and-ship: kitting, labelling, bundling, returns processing, relabelling for a marketplace's rules. VAS charges are the invoice lines most likely to leak, because the work happens off the standard flow — a kitting job done as a favour on Tuesday is invisible on the 31st unless it was captured as a billable event while the tape gun was still warm.

One unit of chargeable work, recorded with a client, a rate and a timestamp: a pallet received, an order picked and packed, a kit assembled, a return processed, a week of a pallet's storage. A 3PL's revenue is the sum of its billable events — which is why the difference between capturing them as the work happens and reconstructing them at month-end is the difference between near-zero and the industry's typical 3–15% revenue leakage.

The per-client price list: what this particular client pays for receiving, storage, pick and pack, VAS and surcharges. Every client's card is different — negotiated at the deal, applied at the event. A rate card that lives in the sales email rather than in the billing system is how the work, the agreement and the invoice end up as three documents that have never met.

The discipline of keeping each client's inventory, transactions, documents and reporting separate on a shared floor. It is the defining requirement of 3PL software: a standard WMS assumes one inventory owner, so it has nowhere to put the fact that bay A-14 belongs to one client and A-15 to another. Segregation is what makes the mixed floor possible — pallet clients, item-level clients and batch-expiry clients on the same racks, with no cross-contamination of counts.

The client's own window into their slice of your warehouse: stock on hand, inbounds in progress, order status, activity history. Every question the portal answers is an email you didn't receive and a walk of the floor nobody had to make. It is also quiet commercial armour — a client who can see their own storage snapshots rarely disputes the storage line.

Two granularities of inventory. SKU (item-level) tracking follows individual sellable units — mandatory for e-commerce fulfilment, where orders are picked one item at a time. Pallet-level tracking treats the whole pallet as the unit — right for bulk storage clients where nobody ever opens the shrink wrap. A working 3PL floor usually needs both at once, on a per-client basis, which is precisely the situation single-granularity systems handle badly.

Three software layers, regularly confused in vendor brochures. A WMS (warehouse management system) runs inventory, people and process — what's where, who picks what, what gets billed. A WCS (warehouse control system) drives machinery — conveyors, sorters, scanner tunnels. A WES (warehouse execution system) sits between the two, orchestrating work in real time. Most 3PLs live entirely in the WMS layer; you meet the other two acronyms when serious automation hardware arrives on the floor.

The gap between the work a warehouse did and the work it invoiced: unrecorded VAS jobs, storage days that never reached the invoice, surcharges nobody applied, receiving counted at the dock but never priced. Typical 3PL leakage runs 3–15% of revenue; best-in-class operations hold it under 0.1%. It is not a pricing problem — it is a capture problem. The work happened. The record didn't.

A scheduled record of what each client had in storage — pallets, bins or square feet — taken on a rhythm (daily, weekly) so that storage billing is computed from evidence rather than reconstructed at month-end from memory and a walk of the floor. When a client asks why they were billed to the 19th when they shipped on the 12th, the snapshot sequence is the answer that ends the meeting.

An escalating charge applied by rule to stock that has overstayed the threshold agreed in the client's rate card. The purpose is honest economics: aged stock occupies bins that could be turning, so the surcharge either moves the stock or pays for the space. Roughly 48.6% of warehouses now charge them, per one industry survey — a single-source figure, so treat it as indicative. The operational catch: a surcharge rule that no system enforces is just a discount nobody agreed to.