Definition

1. Adjective:
   • Antiparallel: In geometry, describes two lines or vectors that are parallel but point in exactly opposite directions.

Usage Examples

• Adjective:
  • Hai vectơ này là đối song. (These two vectors are antiparallel.)
  • Đường thẳng AB và CD là đối song với nhau. (Lines AB and CD are antiparallel to each other.)

Advanced Usage

• Used primarily in mathematical and scientific contexts (e.g., geometry, physics) to describe directional opposition in parallel entities.

Variants and Related Words

• Song song (adj): parallel (pointing in the same direction).
• Ngược hướng (adj): opposite in direction (a more general term, not necessarily implying parallelism).

Synonyms

• Antiparallel: The direct and primary synonym in English technical language.

Notes

• This is a specialized technical term. Its usage is almost exclusively confined to mathematical descriptions.