"a salient angle or part, a projection," especially as part of a military work, 1828, from salient (adj.).
city in Spain, Roman Pompeiopolis, named for Pompey the Great, Roman military leader who founded it 68 B.C.E.
"demand or require (something) to be furnished" for military or public purposes, 1837, from requisition (n.). Related: Requisitioned; requisitioning.
1610s, "a defensive military watchtower;" perhaps a shortened variant of sentinel, which had a variant form centrinel (1590s); or perhaps it is from sentry, a 16c. worn-down form of sanctuary (n.), on the notion of "shelter for a watchman." The meaning "military guard posted around a camp" is attested by 1630s. Sentry-box, "booth to give shelter to a sentry in bad weather," is from 1728.