vertical angle. An opposite angle (see opposite, adj. 1a).
An angle of 120°, comprising one-third of the circumference of a circle; in Astrology = trine, n. 2 (also adj. = trine, adj. 2).
Mathematics. A vertical angle (see A. 2).
A re-entrant angle. Obsolete. rare.
The angle swept out by a line in turning once completely around one end as centre; an angle of 360 degrees, or four right angles.