morning: [13] The Old English word for ‘morning’ was morgen. It came from a prehistoric Germanic *murganaz (source also of German, Dutch, and Danish morgen ‘morning’), and links have been suggested with forms such as Old Church Slavonic mruknati ‘darken’ and Lithuanian mirgeti ‘twinkle’, which may point to an underlying etymological notion of the ‘glimmer of morning twilight’.
By the Middle English period the word morgen had evolved to what we now know as morn, and morning was derived from it on the analogy of evening. A parallel development of morgen was to Middle English morwe, from which we get modern English morrow (and hence tomorrow). => morn, tomorrow
mid-13c., morn, morewen (see morn) + suffix -ing, on pattern of evening. Originally the time just before sunrise. As an adjective from 1530s. Morning after in reference to a hangover is from 1884; in reference to a type of contraception, attested from 1867. Morning sickness as a symptom of pregnancy is from 1793 (Old English had morgenwlætung). Morning glory is from 1814, in reference to the time the flowers open. Morning star "Venus in the east before sunrise" is from 1530s (Old English had morgensteorra "morn-star"). As a greeting, short for good morning, attested by 1895.