angle

The root angle comes from Latin angulus, "a corner" — the sharp meeting point where two lines or walls come together. The image is purely geometric, and the whole family is built by counting corners.

Start with the number prefixes:
- tri- (three) + angle → triangle: a shape with three corners.
- rect- (straight, right) + angle → rectangle: a shape whose corners are all right angles (ninety degrees).
- quadr- (four) + angle → quadrangle: a four-cornered shape — and, in British universities, the four-sided courtyard enclosed by buildings.

Notice the pattern: the prefix tells you how many corners (or what kind of corner), and angle stays constant as "the corner." Add the adjective ending -ar and you describe the shape: triangular, rectangular.

Beyond geometry, English uses the bare word angle figuratively for a point of view: a journalist looks for a fresh angle on a story, the way you'd look at a sculpture from a new corner of the room. Same idea — the position from which lines (or thoughts) meet.

One warning about a lookalike: anguish (deep suffering) is not a member of this family, even though it starts with the same letters. It comes from Latin angere, "to choke, to press tight" (the same source as anxious and anger). The overlap is a coincidence of spelling — a corner (angulus) and a tightening grip (angere) are unrelated in Latin. Keep them apart: shapes and corners → angle; squeezing distress → anguish/anxious.