D defs.my
Entry 1 sense Webster, 1913

Subtend

· Sub·tend · IPA /sʌbˈtɛnd/
01 v. t. To extend under, or be opposed to; as, the line of a triangle which subtends the right angle; the chord subtends an arc.
imp. & p. p. Subtended; p. pr. & vb. n. Subtending
  1. 1.
    To extend under, or be opposed to; as, the line of a triangle which subtends the right angle; the chord subtends an arc.