Webster's Revised Unabridged Dictionary · 1913

Grating

Grating , noun

[See 2d Grate.]

1.
A partition, covering, or frame of parallel or cross bars; a latticework resembling a window grate; as, the grating of a prison or convent.

Gratings have been made with over 40,000 such lines to the inch, but those with a somewhat smaller number give the best definition. They are used, for example, to produce monochromatic light for use in optical instruments such as spectrophotometers.

2.
(Optics) A system of close equidistant parallel lines or bars, esp. lines ruled on a polished surface, used for producing spectra by diffraction; -- called also diffraction grating.
3.
(Nautical) The strong wooden lattice used to cover a hatch, admitting light and air; also, a movable Lattice used for the flooring of boats.

Grating , adjective

[See Grate to rub harshy.]

That grates; making a harsh sound; harsh.

Grating , noun

A harsh sound caused by attrition.