Synonyms for Diameter:

n.

curvature, line, chord, diagonal, arc, axis, outline, horizontal, inclined plane. diameter (noun)
diam.
measurement across object (noun)
broadness, width, breadth, caliber.
thickness (noun)
density, caliber, width, expanse, thickness, bulk, breadth.
width (noun)
breadth.

v.

bore (verb)
measurement across, broadness.

Other synonyms:

horizontal, inclined plane, diagonal. chord, curvature, axis. outline, arc. line. Other relevant words:
curvature, broadness, horizontal, diam, chord, arc, outline, diagonal, axis, line.

Usage examples for diameter

  1. The leech was over sixty miles in diameter now and still growing fast. – The Leech by Phillips Barbee
  2. The tower is about 20 feet in diameter – Castles and Cave Dwellings of Europe by Sabine Baring-Gould
  3. A circle about three feet in diameter is drawn on the floor in the front of the room and serves as a goal. – Games for the Playground, Home, School and Gymnasium by Jessie H. Bancroft