The Collaborative International Dictionary of English v.0.48:

Truncate \Trun"cate\, a. [L. truncatus, p. p. ]
   Appearing as if cut off at the tip; as, a truncate leaf or
   feather.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Truncate \Trun"cate\, v. t. [imp. & p. p. Truncated; p. pr. &
   vb. n. Truncating.] [L. truncatus, p. p. of truncare to cut
   off, mutilate, fr. truncus maimed, mutilated, cut short. See
   Trunk.]
   To cut off; to lop; to maim.
   [1913 Webster]

WordNet (r) 3.0 (2006):

truncate
    adj 1: terminating abruptly by having or as if having an end or
           point cut off; "a truncate leaf"; "truncated volcanic
           mountains"; "a truncated pyramid" [syn: truncate,
           truncated]
    v 1: replace a corner by a plane
    2: approximate by ignoring all terms beyond a chosen one;
       "truncate a series"
    3: make shorter as if by cutting off; "truncate a word";
       "Erosion has truncated the ridges of the mountains" [syn:
       truncate, cut short]