Fundamentals

Ocean Shipping Glossary: 30 Terms Every Forwarder Should Know

Ocean freight has a dialect, and half of it is acronyms. This glossary covers the terms that actually come up on an operations desk — defined in plain language, grouped so they make sense together.

CTCargoScope TeamJune 5, 20269 min read

Key takeaways

  • Ocean freight vocabulary clusters into parties, documents, journey events, time/cost, equipment, and operations.
  • The money terms — free time, LFD, demurrage, detention, per diem — are the ones worth memorizing first.
  • A container number identifies the box; a booking number identifies the booked shipment before containers are assigned.
  • Most 'delays' trace back to a hold blocking availability while free time keeps counting.

People and parties

  • BCO (Beneficial Cargo Owner) — the actual owner of the goods, who moves cargo under their own contracts rather than through a forwarder.
  • Freight Forwarder — a company that arranges shipping on behalf of shippers, coordinating carriers, customs, and inland moves.
  • NVOCC — a carrier that does not operate ships but issues its own bills of lading, buying space from vessel operators.
  • Consignee — the party receiving the shipment at destination.
  • Drayage Provider — the trucker who moves the container between the port/terminal and its next stop.

Documents and identifiers

  • Container Number — the box's unique ID: four letters plus seven digits (e.g., MSCU5829104).
  • Booking Number — the reference for a booked shipment with a carrier, used before container numbers are assigned.
  • Bill of Lading (B/L) — the carrier's contract of carriage and receipt for the goods; also a document of title.
  • SCAC — the Standard Carrier Alpha Code identifying a carrier.
  • HBL / MBL — House and Master Bills of Lading; the forwarder issues the house, the carrier issues the master.

The journey

  • Gate In / Gate Out — the container entering or leaving a terminal; gate-out (outgate) is pickup.
  • Loaded / Discharged — lifted onto or off the vessel.
  • Transshipment — transferring cargo from one vessel to another at an intermediate hub.
  • Rolled Cargo — a container bumped to a later sailing, usually from overbooking or a schedule slip.
  • Empty Return — bringing the emptied container back to the carrier, closing the cycle.

Time and cost

  • ETA / ETD — Estimated Time of Arrival / Departure.
  • Free Time — the days allowed before demurrage or detention charges begin.
  • LFD (Last Free Day) — the deadline before demurrage starts at the terminal.
  • Demurrage — charges for a container overstaying inside the terminal after arrival.
  • Detention — charges for holding a container outside the terminal too long after pickup.
  • Per Diem — the daily rate charged for detention on the carrier's equipment.

Equipment and vessel

  • TEU / FEU — Twenty- and Forty-foot Equivalent Units, the standard container size measures.
  • Chassis — the wheeled frame a container sits on for road transport.
  • Reefer — a refrigerated container for temperature-controlled cargo.
  • Vessel / Voyage — the ship and its specific numbered sailing.
  • AIS — the Automatic Identification System vessels use to broadcast position at sea.

Operations and holds

  • Hold — a block (customs, agency, line, or unpaid fee) preventing a container's release.
  • Availability — the point at which a discharged container is released for pickup.
  • Appointment — a booked slot to pick up or drop off at a terminal that uses appointment systems.
  • Demurrage Clock — the running count of days past free time while a box sits at the terminal.
  • Exception — any shipment that has deviated from plan and needs attention.

Frequently asked

What's the difference between a booking number and a container number?

A booking number references a booked shipment with a carrier and exists before equipment is assigned. A container number identifies a specific physical box. Early in a shipment you may only have the booking number; later you track by container.

Is per diem the same as detention?

They overlap. Per diem is the daily rate charged for keeping the carrier's equipment out too long; detention is the charge that rate produces. In practice teams use the terms interchangeably for the outside-the-terminal clock.

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