The Collaborative International Dictionary of English v.0.48:

nonparallel \nonparallel\ adj.
   1. not parallel; -- of lines or linear objects. Opposite of
      parallel. [Narrower terms: bias, catacorner,
      cata-cornered, catercorner, cater-cornered, catty-corner,
      catty-cornered, diagonal, kitty-corner, kitty-cornered,
      oblique, skew, skewed, slanted ; {crossed, decussate,
      intersectant, intersecting; cross-grained ; {diagonal;
      orthogonal, orthographic, rectangular, right-angled ;
      {right, perpendicular; angled ; {convergent] Also See:
      convergent, divergent, diverging.
      [WordNet 1.5]

   2. (Computers) Not using parallel processing; -- of
      computers. [Narrower terms: serial] PJC]

The Collaborative International Dictionary of English v.0.48:

Convergent \Con*ver"gent\, a. [Cf. F. convergent.]
   tending to one point of focus; tending to approach each
   other; converging.
   [1913 Webster]

         As many rays of light, as conveniently can be let in,
         and made convergent.                     --Boyle.
   [1913 Webster]

         The vast dome of its cathedral . . . directing its
         convergent curves to heaven.             --Hallam.
   [1913 Webster]

WordNet (r) 3.0 (2006):

convergent
    adj 1: tending to come together from different directions [ant:
           divergent, diverging]