"rectangular wooden container," usually with a lid, Old English box, also the name of a type of shrub, from Late Latin buxis, from Greek pyxis "boxwood," pyxion "writing table, box," made of boxwood, from pyxos "box tree," which is of uncertain origin. Beekes suggests a loan-word from Italy, as that is where the tree is native. Dutch bus, German Büchse "box; barrel of a gun," also are Latin loan-words.
Meaning "compartment at a theater" is from c. 1600 (box seat in the theatrical sense is by 1850). Meaning "pigeon-hole at a post office" is from 1832. Meaning "television" is from 1950 (earlier "gramphone player," 1924). Meaning "station of a player in baseball" is from 1881. Graphics sense "space enclosed within borders and rules" is from 1929. Slang meaning "vulva" is attested 17c., according to "Dictionary of American Slang;" modern use seems to date from c. World War II, perhaps originally Australian, on notion of "box of tricks." Box lunch (n.) attested from 1899. The box set, "multiple-album, CD or cassette issue of the work of an artist" is attested by 1955. To think or act outside the box "contrary to convention" is attested by 1994.