Search Result for "antiparallel": 
Wordnet 3.0

ADJECTIVE (1)

1. (especially of vectors) parallel but oppositely directed;
- Example: "antiparallel vectors"



The Collaborative International Dictionary of English v.0.48:

Antiparallel \An`ti*par"al*lel\, a.
   Running in a contrary direction. --Hammond.
   [1913 Webster]


WordNet (r) 3.0 (2006):

antiparallel
    adj 1: (especially of vectors) parallel but oppositely directed;
           "antiparallel vectors"