acquired or related by adoption: an adoptive father or son.
3.
tending to adopt.
Origin: 1400–50; < L adoptīvus;see adopt, -ive; r. late ME adoptife < MF adoptif
Related forms:
a⋅dop⋅tive⋅ly, adverb
Usage note: Although adoptive in the sense “acquired or related by adoption” can refer to either parent or child in such a relationship, adoptive is customarily applied to the parent (her adoptive mother) and adopted to the child (their adopted son).
Related by adoption: "increased honesty and sharing between birth families, adoptive families and adoptees"(Robyn S. Quinter). See Usage Note at adopt.
Main Entry: adop·tive Pronunciation: &-'däp-tiv Function: adjective 1 a: having adopted adoptive parent> b: having been adopted adoptive child> 2: made or acquired by accepting as one's own the words or actions of another adoptive admission…defendant must actually understand what was said and have an opportunity to deny it —United States v. White, 766 Federal Reporter Supp. 873 (1991)>
[uh-dop-tiv] 
tɪv