adverb

During the period of time preceding a particular event or time.

my playing days had ended six years before

previously,before now,before then,until now,until then,up to now,up to then

preposition

During the period of time preceding (a particular event or time)

she had to rest before dinner

prior to,previous to,earlier than,preparatory to,in preparation for,preliminary to,in anticipation of,in expectation of

conjunction

In advance of the time when.

they lived rough for four days before they were arrested