D defs.my
Entry 1 sense Webster, 1913

Antiparallels

· An·ti·par·al·lels · IPA
01 n. pl. Straight lines or planes which make angles in some respect opposite in character to those made by parallel lines or planes.
  1. 1.
    Straight lines or planes which make angles in some respect opposite in character to those made by parallel lines or planes.(Geom.)