A small wheel or roller, specifically the wheel of a gun carriage.

The ball on top of a flagpole.

(nautical) On a wooden mast, a circular disc (or sometimes a rectangle) of wood near or at the top of the mast, usually with holes or sheaves to reeve signal halyards; also a temporary or emergency place for a lookout. "Main" refers to the mainmast, whereas a truck on another mast may be called (on the mizzenmast, for example) "mizzen-truck".

(countable, uncountable, US, Australia) A heavier motor vehicle designed to carry goods or to pull a semi-trailer designed to carry goods.

(road transport, Singapore, Malaysia) A lorry with a closed or covered carriage.

(UK, rail transport) A railroad car, chiefly one designed to carry goods

(US, rail transport) Abbreviation of railroad truck or wheel truck; a pivoting frame, one attached to the bottom of the bed of a railway car at each end, that rests on the axle and which swivels to allow the axle (at each end of which is a solid wheel) to turn with curves in the track.

The part of a skateboard or roller skate that joins the wheels to the deck, consisting of a hanger, baseplate, kingpin, and bushings, and sometimes mounted with a riser in between.

(theater) A platform with wheels or casters.

Dirt or other messiness.

(historical) The practice of paying workers in kind, or with tokens only exchangeable at a shop owned by the employer [forbidden in the 19th century by the Truck Acts].

(US, often attributive) Garden produce, groceries (see truck garden).

(usually with negative) Social intercourse; dealings, relationships.

(intransitive) To drive a truck.

(transitive) To convey by truck.

(intransitive, US, slang) To travel, to proceed.

(intransitive, US, Canada, slang) To persist, to endure.

(intransitive, film production) To move a camera parallel to the movement of the subject.

(transitive, slang) To fight or otherwise physically engage with.

(transitive, slang) To run over or through a tackler in American football.

(transitive) To trade, exchange; barter.

(intransitive) To engage in commerce; to barter or deal.

(intransitive) To have dealings or social relationships with; to engage with.