definition of
grating

[1] #1 grating n. [grate] a barrier that has parallel or crossed bars blocking a passage but admitting air. wn

[2] #2 grating s. [gravelly, rasping, raspy, rough, scratchy] unpleasantly harsh or grating in sound; "a gravelly voice". wn

[3] #3 grating n. [grate] a frame of iron bars to hold a fire. wn

[4] #4 grating n. [diffraction grating] optical device consisting of a surface with many parallel grooves in it; disperses a beam of light (or other electromagnetic radiation) into its wavelengths to produce its spectrum. wn