of grate-a partition, covering, or frame of parallel or cross bars; a latticework resembling a window grate; as, the grating of a prison or convent.-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.-the strong wooden lattice used to cover a hatch, admitting light and air; also, a movable lattice used for the flooring of boats.-that grates; making a harsh sound; harsh.-a harsh sound caused by attrition.