a fixed frame of bars or the like covering an opening to exclude persons, animals, coarse material, or objects while admitting light, air, or fine material.

Physics . diffraction grating.

adjective

pleasing , soothing

adjective

annoying , disagreeable , discordant , displeasing , dissonant , dry , grinding , harsh , harsh-sounding , hoarse , irksome , jarring , offensive , rasping , raucous , rough , shrill , squeaky , strident , stridulent , stridulous , unpleasant , vexatious , raspy , scratchy , squawky , grid