An Etymological Dictionary of the German Language/Annotated/Morgen
Morgen (1.), masculine, ‘morning,’ from the equivalent Middle High German morgen, Old High German morgen, masculine; compare Old Saxon morgan, Dutch morgen, Anglo-Saxon morgen, mergen, masculine, English morning (with the suffix -ing as in evening), Old Icelandic morgunn and myrgenn, Gothic maurgins, masculine; the common Teutonic term for the first half of the day, commencing with the dawn. It does not obtain, however, in the non-Teutonic languages, being, like Tag and Abend (Gothic undaurns, ‘midday’), specifically Teutonic. The pre-Teutonic mṛkeno- or mṛgheno- is still obscure; some etymologists connect it with Gothic maúrgjan, ‘to shorten,’ but this gives no definite sense for Morgen. With greater probability may Old Slovenian mrŭknąti, ‘to grow dark,’ mrakŭ, ‘darkness,’ be allied to the Teutonic cognates, so that Morgen might be regarded as ‘dawn’; compare the development of meaning in Dämmerung. —
morgen, in the sense of ‘to-morrow,’ is from Middle High German morgen, Old High German morgane, properly a dative singular, ‘in the morning, especially of the following day, (on) the next day’; similarly French demain, lendemain, from Latin mane. This use of morgen is unknown to Gothic (compare gestern); Scandinavian has á morgun, English to-morrow; Middle English tô morwe, dative, from morge(n), Dutch morgen, ‘to-morrow.’ Abend is similarly used of the preceding day (see also Sonnabend). —
Morgen, ‘east,’ is similar to the meaning of Latin mane in the Romance languages. Compare the origin of Osten.
Morgen (2.). masculine, from the equivalent Middle High German morgen, Old High German morgan, masculine, ‘acre’ (or nearly so); usually identified with Morgen (1), ‘morning's work for a team, the space ploughed by a team in a morning’; similarly Middle Latin dies, ‘tantum terræ quantum quis per diem uno aratro arare potest.’ So too Middle Latin diurnalis, ‘a square measure.’