What is "axle guard"

Axle guard \Ax"le guard`\ The part of the framing of a railway car or truck, by which an axle box is held laterally, and in which it may move vertically; -- also called a jaw in the United States, and a housing in England.

n. The part of the framing of a railway car or truck, by which an axle box is held laterally, and in which it may move vertically.