The Collaborative International Dictionary of English v.0.48:

Gangrene \Gan"grene\, n. [F. gangr[`e]ne, L. gangraena, fr. Gr.
   ?, fr. ? to gnaw, eat; cf. Skr. gras, gar, to devour, and E.
   voracious, also canker, n., in sense 3.] (Med.)
   A term formerly restricted to mortification of the soft
   tissues which has not advanced so far as to produce complete
   loss of vitality; but now applied to mortification of the
   soft parts in any stage.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gangrene \Gan"grene\, v. t. & i. [imp. & p. p. Gangrened; p.
   pr. & vb. n. Gangrening.] [Cf. F. gangr['e]ner.]
   To produce gangrene in; to be affected with gangrene.
   [1913 Webster]

WordNet (r) 3.0 (2006):

gangrene
    n 1: necrotic tissue; a mortified or gangrenous part or mass
         [syn: gangrene, sphacelus, slough]
    2: the localized death of living cells (as from infection or the
       interruption of blood supply) [syn: necrosis,
       mortification, gangrene, sphacelus]
    v 1: undergo necrosis; "the tissue around the wound necrosed"
         [syn: necrose, gangrene, mortify, sphacelate]