morn n.

a word used to denote the marriage of a man of high rank to a woman of lower station with stipulations limiting her claims, also of the marriage of a woman of high rank to a man of lower station; 1727, from French morganatique (18c.), from Medieval Latin matrimonium ad morganaticam "marriage of the morning," probably from Old High German *morgangeba (Middle High German morgengabe) "morning gift," corresponding to Old English morgengifu (see morn + gift (n.) ).

In an unequal marriage between a man of royal blood and a common woman, this was a gift traditionally given to the wife on the morning after consummation, representing the only share she and her children may claim in the husband's estate. Also known as left-handed marriage, because the groom gives the bride his left hand instead of his right, but sometimes this latter term is used of a of marriage (especially in Germany) where the spouse of inferior rank is not elevated, but the children inherit rights of succession. Related: Morganatically.

1620s, an old measure of land in Holland (hence also in South Africa and colonial New York and New Jersey), roughly two acres but sometimes less, probably identical with Dutch morgen "morning" (see morn) and meaning "the amount of land one man can plow in a morning."