In ancient times, a cohort was a military unit, one of ten divisions in
a Roman legion. The term passed into English in the 15th century, when
it was used in translations and writings about Roman history. Once
cohort
became established in our language, its meaning was extended, first to
refer to any body of troops, then to any group of
individuals with
something in common, and later to a single companion. Some usage
commentators have objected to this last sense because it can be hard to
tell whether the plural refers to different individuals or different
groups. The "companion" sense is well established in standard use,
however, and its meaning is clear enough in such sentences as "her
cohorts came along with her to the game."
