(1):

(v. t.) To take or receive as one's own what is not so naturally; to select and take or approve; as, to adopt the view or policy of another; these resolutions were adopted.

(2):

(v. t.) To take by choice into relationship, as, child, heir, friend, citizen, etc.; esp. to take voluntarily (a child of other parents) to be in the place of, or as, one's own child.