The Collaborative International Dictionary of English v.0.48:
Espouse \Es*pouse"\, v. t. [imp. & p. p. Espoused; p. pr. &
vb. n. Espousing.] [OF. espouser, esposer, F. ['e]pouser,
L. sponsare to betroth, espouse, fr. sponsus betrothed, p. p.
of spondere to promise solemnly or sacredly. Cf. Spouse.]
1. To betroth; to promise in marriage; to give as spouse.
A virgin espoused to a man whose name was Joseph.
--Luke i. 27.
2. To take as spouse; to take to wife; to marry.
Lavinia will I make my empress, . . .
And in the sacred Pantheon her espouse. --Shak.
3. To take to one's self with a view to maintain; to make
one's own; to take up the cause of; to adopt; to embrace.
"He espoused that quarrel." --Bacon.
Promised faithfully to espouse his cause as soon as
he got out of the war. --Bp. Burnet.