(rail transport, colloquial) the space between the rails on a standard gauge railway line.

(curling): Alternative form of 4-foot

A large four-masted sailboat.

(automotive, engineering) Having four wheels.

A small cake generally eaten at the end of a meal or served as part of a large buffet.

(mathematics) A vector in four-dimensional vector space, especially one having three spatial dimensions and one temporal dimension.

plural of four-seamer

(automotive) Abnormal operation of a two-stroke internal combustion engine, such that the cylinder only fires every second cycle (like a four-stroke engine). This occurs when the exhaust scavenging and inlet charging leaves a mixture in the cylinder which does not ignite, but needs a second scavenge/charge to produce an adequate mix.

having four doors

A motor car with four doors.