The Collaborative International Dictionary of English v.0.48:

Bekah \Be"kah\, n. [Heb.]
   Half a shekel.
   [1913 Webster]

Easton's 1897 Bible Dictionary:

Bekah
   Both the name and its explanation, "a half shekel," are given in
   Ex. 38:26. The word properly means a "division," a "part."
   (R.V., "beka.")


Hitchcock's Bible Names Dictionary (late 1800's):

Bekah, half a shekel