Dictionary
sub•tend
Pronunciation: (sub-tend', sub-), [key]—
v.t.
1. Geom.to extend under or be opposite to:
a chord subtending an arc.
2. Bot.(of a leaf, bract, etc.) to occur beneath or close to.
3. to form or mark the outline or boundary of.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.