An Etymological Dictionary of Astronomy and Astrophysics

1a) A large number of persons gathered closely together; throng.

1b) Any large number of persons.

1c) Any group or set of persons with something in common.

2. To gather in large numbers; throng; swarm (Dictionary.com).
   → crowded, → crowded field, → crowding.

Etymology (EN): M.E. crowden, from O.E. crudan “to press, crush;” akin to
M.Du. cruden “to press, push,” M.H.G. kroten “to press, oppress,” Norwegian kryda “to crowd.”

Etymology (PE): Capiré (Dehxodâ), variants cabiré, capar “crowd,
troop, people gathered for something.” Capiré, from capir, from capar, ultimately from Proto-Ir. *ui-par-, from *par- “to fill;” cf. Av. pər- “to fill, stuff with,” pouru- “full, much, many;” O.Pers. paru- “much, many;” Pers. anbâr “ricks, storehouse,” por, bol “full, much, many;” PIE *pel- “to fill;” → population.