The Collaborative International Dictionary of English v.0.48:

Earmark \Ear"mark`\, v. t. [imp. & p. p. Earmarked; p. pr. &
   vb. n. Earmarking.]
   1. To mark, as sheep, by cropping or slitting the ear.
      [1913 Webster]

   2. To designate or reserve for a specific purpose; as, the
      alumni fund was earmarked for dormitory construction.
      [PJC]