The Collaborative International Dictionary
Subtend \Sub*tend"\, v. t. [imp. & p. p. Subtended; p. pr. & vb. n. Subtending.] [L. subtendere; sub under + tendere to stretch, extend. See Tend.] To extend under, or be opposed to; as, the line of a triangle which subtends the right angle; the chord subtends an arc.
Wiktionary
vb. (present participle of subtend English)
Usage examples of "subtending".
I had also hoped to find a virgin region lying beyond El-Harrah, the volcanic tract subtending the east of the Hisma, or plateau of New Red Sandstone.
Mars and Tellus are subtending an angle of something more then ninety degrees at the sun, and Venus is between the two, while Jupiter is clear across the sun from all three of them.
The upper one, as seen from an inverting telescope, appeared double-headed, like one near the Dolphin, but much more decided than that, the space between the two heads being very plainly discernible and subtending a decided angle.
That angle alpha would be identical to the angle-call it beta-at the center of the Earth subtending the 160-stadia chord of the light shaft.