The Collaborative International Dictionary of English v.0.48:

Incisure \In*cis"ure\ (?; 277), n. [L. incisura: cf. F.
   incisure.]
   A cut; an incision; a gash. --Derham.
   [1913 Webster]

WordNet (r) 3.0 (2006):

incisure
    n 1: (anatomy) a notch or small hollow [syn: incisure,
         incisura]