Толковый словарь английского языка Oxford English Reference - elytron

n. (pl. elytra) the outer hard usu. brightly coloured wing-case of a coleopterous insect. Etymology: Gk elutron sheath EM pron. colloq. them (let 'em all come). Etymology: orig. a form of ME hem, dative and accus. 3rd pers. pl. pron.: now regarded as an abbr. of THEM EM n. Printing 1 a unit for measuring the amount of printed matter in a line, usually equal to the nominal width of capital M. 2 a unit of measurement equal to 12 points. Phrases and idioms em rule (or dash) a long dash used in punctuation. Etymology: name of the letter M