Merriam-Webster Collegiate Dictionary - before

 I. adverb or adjective  Etymology: Middle English, adverb & preposition, from Old English beforan, from be- + foran ~, from fore  Date: ~ 12th century  1. in advance ; ahead marching on ~  2. at an earlier time ; previously the night ~ knew her from ~  II. preposition  Date: ~ 12th century  1.  a.  (1) forward of ; in front of stood ~ the fire  (2) in the presence of speaking ~ the conference  b. under the jurisdiction or consideration of the case ~ the court  c.  (1) at the disposal of the great sums placed ~ him  (2) in store for got the whole summer ~ you  2. preceding in time ; earlier than just ~ noon  3. in a higher or more important position than put quantity ~ quality  III. conjunction  Date: 13th century  1.  a.  (1) earlier than the time that call me ~ you go  (2) sooner or quicker than I'll be done ~ you know it  (3) so that…do not get out of there ~ you get dirty  b. until the time that miles to go ~ I sleep — Robert Frost  c.  (1) or else…not must be convicted ~ he can be removed from office  (2) or else get out of here ~ I call a cop  2. rather or sooner than would starve ~ he'd steal