OXFORD DICTIONARY
subtend, v.tr.
1 a (usu. foll. by at) (of a line, arc, figure, etc.) form (an angle) at a particular point when its extremities are joined at that point. b (of an angle or chord) have bounding lines or points that meet or coincide with those of (a line or arc).
2 Bot. (of a bract etc.) extend under so as to embrace or enfold.
L subtendere (as SUB-, tendere stretch)
THESAURUS
subtend
bump heads, confront, contend, contrapose, contraposit, contrast, counteract, face, front, lie opposite, match, meet head-on, oppose, polarize, pose against, put in opposition, set over against, stand opposed, stand opposite