subtend

 
Pronunciation: /sʌbˈtɛnd/

verb

[with object]
  • 1 Geometry (of a line, arc, or figure) form (an angle) at a particular point when straight lines from its extremities are joined at that point: the angle subtended by a string of length r at the centre of the sphere
  • (of an angle or chord) have bounding lines or points that meet or coincide with those of (a line or arc).
  • 2 Botany (of a bract) extend under (a flower) so as to support or enfold it: the main beauty is provided by the bracts which subtend the flowers

Origin:

late 16th century (in subtend (sense 1)): from Latin subtendere, from sub- 'under' + tendere 'stretch'. subtend (sense 2) dates from the late 19th century