Source : Webster's Revised Unabridged Dictionary (1913)

Upstroke \Up"stroke`\, n.
   An upward stroke, especially the stroke, or line, made by a
   writing instrument when moving upward, or from the body of
   the writer, or a line corresponding to the part of a letter
   thus made.

         Some upstroke of an Alpha and Omega.     --Mrs.
                                                  Browning.

Source : WordNet®

upstroke
     n : a stroke normally made in an upward direction