Source : Webster's Revised Unabridged Dictionary (1913)

Jerkin \Jer"kin\, n. [Dim. of D. jurk a frock.]
   A jacket or short coat; a close waistcoat. --Shak.

Jerkin \Jer"kin\, n. (Zo["o]l.)
   A male gyrfalcon.

Source : WordNet®

jerkin
     n : a tight sleeveless and collarless jacket (often made of
         leather) worn by men in former times