Jacket: A wood or fiber cover placed around such containers as cans and bottles.

Jacob's Ladder: A rope ladder suspended from the side of a vessel and used for boarding.

Jettison: Act of throwing cargo or equipment (jetsam) overboard when a ship is in danger.

Just-In-Time (JIT): With this method of inventory control, warehousing is minimal or non-existent. The container is the movable warehouse and must arrive "just-in-time" - not too early, not too late.

Joint Rate: A rate applicable from a point on one transportation line to a point on another line, made by agreement and published in a single tariff by all transportation lines over which the rate applies.