grating

Concise Oxford English Dictionary © 2008 Oxford University Press:
grating1

▶adjective

• 1 sounding harsh and unpleasant.

• 2 causing irritation.

– derivatives
gratingly adverb.

Concise Oxford English Dictionary © 2008 Oxford University Press:
grating2

▶noun

• 1 a framework of parallel or crossed bars, typically preventing access through an opening.

• 2 (also diffraction grating) Optics a set of equally spaced parallel wires or ruled lines, used to produce spectra by diffraction.