grating line frequency

grating

— noun (= grate) a barrier that has parallel or crossed bars blocking a passage but admitting air — adjective (= gravelly) unpleasantly harsh or grating in sound a gravelly voice — noun (= grate) a frame of iron bars to hold a fire — noun (= 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

line Noun

— A mark that is long, straight and very thin. She drew a line down the middle of the page to divide the page into two parts. — A row. Put the buttons in a straight line on the front of the shirt. — A row of people who are waiting for something in order; a queue. You got here last, so you have to stand at the back of the line.

line Verb

— Someone lines things up when they put them in a straight line or row. — Someone lines something up when they put it just in the right place or at the edge of something. Line up the end of the piece of wood with the edge of the table. — Someone lines up when they start waiting in a line (queue) with other people. Everyone line up here, please, and I'll help you one at a time. — Someone lines something when they mark it with one or more lines. Please line the pitch before the match. — Someone lines something when they add an inside layer of material (liner) to it.

frequency Noun

— Something's frequency is how often it happens. A frequency of one hertz is an event repeated once per second.