The Collaborative International Dictionary of English v.0.48:
Prime \Prime\, v. t. [imp. & p. p. Primed; p. pr. & vb. n.
Priming.] [From Prime, a.]
1. To apply priming to, as a musket or a cannon; to apply a
primer to, as a metallic cartridge.
2. To lay the first color, coating, or preparation upon (a
surface), as in painting; as, to prime a canvas, a wall.
3. To prepare; to make ready; to instruct beforehand; to
post; to coach; as, to prime a witness; the boys are
primed for mischief. [Colloq.] --Thackeray.
4. To trim or prune, as trees. [Obs. or Prov. Eng.]
5. (Math.) To mark with a prime mark.
To prime a pump, to charge a pump with water, in order to
put it in working condition.