Webster's Revised Unabridged Dictionary · 1913

Diametral

Diametral , adjective

[Greek French diamétral.]

Pertaining to a diameter; diametrical.
Collocations (2)
Diametral curve or Diametral surface (Geometry) , any line or surface which bisects a system of parallel chords drawn in a curve or surface.
Diametral planes (Crystal.) , planes in which two of the axes lie.

Diametral , noun

A diameter. [Obsolete] — Sir T. Browne