An Etymological Dictionary of Astronomy and Astrophysics

A → diffraction grating with
a series of grooves that have been ruled on a reflective surface with a diamond tool mounted on a ruling machine. Ruled gratings may have triangular or trapezoidal groove profiles, whereas → holographic gratings usually have sinusoidal groove profiles.

Etymology (EN): Ruled, → rule; → grating.

Etymology (PE): Turi, → grating; šiyârdâr “having grooves,” from šiyâr, → groove, + -dâr “having, possessor,” → property.