I. adverb
1.
so as to precede something in order or time
racing on before to give warning
Synonyms: ahead, ante, antecedently, beforehand, fore, forward, in advance, precedently, previous
Contrasted words: behind; abaft, aft, astern
Antonyms: after
2.
in time past
had heard that joke before
Synonyms: already, earlier, erstwhile, formerly, heretofore, once, previously; compare then 1
Antonyms: after
3.
until now or then
you'll get it tomorrow and not before
Synonyms: beforehand, earlier, sooner
II. preposition
1.
coming before in space or time
be home before dark
Synonyms: ahead of, ante, ere, in advance of, preceding, prior to, to; compare until
Contrasted words: since, subsequent to
Antonyms: after
2.
in the presence of
stood before the court
Synonyms: confronting, facing
Idioms: face to face with
3.
Synonyms: until , in advance of, prior to, till, to, up till, up to