Grating

1. That grates; making a harsh sound; harsh.
2. 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.
3. A harsh sound caused by attrition.
4. A partition, covering, or frame of parallel or cross bars; a latticework resembling a window grate; as, the grating of a prison or convent.
5. of Grate
6. The strong wooden lattice used to cover a hatch, admitting light and air; also, a movable Lattice used for the flooring of boats.