The Collaborative International Dictionary
Morganatically
Morganatic \Mor`ga*nat"ic\, a. [LL. matrimonium ad morganaticam,
fr. morganatica a morning gift, a kind of dowry paid on the
morning before or after the marriage, fr. OHG. morgan
morning, in morgangeba morning gift, G. morgengabe. See
Morn.]
Pertaining to, in the manner of, or designating, a kind of
marriage, called also left-handed marriage, between a man
of superior rank and a woman of inferior, in which it is
stipulated that neither the latter nor her children shall
enjoy the rank or inherit the possessions of her husband.
--Brande & C. -- Mor`ga*nat"ic*al*ly, adv.
Wiktionary
morganatically
adv. In a morganatic manner.