Source : Webster's Revised Unabridged Dictionary (1913)

Yester \Yes"ter\, a. [See {Yesterday}.]
   Last; last past; next before; of or pertaining to yesterday.

         [An enemy] whom yester sun beheld Mustering her charms.
                                                  --Dryden.

   Note: This word is now seldom used except in a few compounds;
         as, yesterday, yesternight, etc.