GRATING

noun a harsh sound caused by attrition.

2. grating ·adj that grates; making a harsh sound; harsh.

3. grating (·p.pr. & ·vb.n.) of grate.

4. grating ·noun the strong wooden lattice used to cover a hatch, admitting light and air; also, a movable lattice used for the flooring of boats.

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

6. grating ·noun a system of close equidistant and parallel lines lines or bars, especially lines ruled on a polished surface, used for producing spectra by diffraction;

— called also diffraction grating.

7. grating ·add. ·noun a system of close equidistant parallel lines or bars, ·esp. lines ruled on a polished surface, used for producing spectra by diffraction. gratings have been made with over 40,000 such lines to the inch, but those with a somewhat smaller number give the best definition.