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.

(archaic) The vanguard or advanced body of an army.

A (comparatively) conservative, reactionary faction that is more unwilling to accept new ideas than their peers are. / Collectively, the members of a team who have been a long time in a place.

Alternative spelling of advance guard

A unit or units leading the way of advancing or marching troops, guarding them from ambushes, reconnoitering and pursuing the enemy, etc. / An individual soldier in the same role.

(idiomatic, cricket) (For a new batsman, with help from the umpire) to mark a point on the popping crease in front of his wicket so that he knows where it is behind him; to guard.

of, or relating to a rearguard / of, or relating to resistance in politics etc

A physical barrier to protect something from unwanted contact, especially a shield to prevent accidental tripping of an emergency shutdown or power switch.

The organisation or officer enforcing maritime law and policing the seas within territorial waters.

A mesh screen placed in front of a fire to prevent sparks escaping.