There are multiple definitions - click on the translation that matches your context.

mãe adotiva

substantivo

full

adoptive parent

noun

Comparative law notes

Portugal

"Mãe adotiva" is narrower in meaning than "adoptive parent". "Adoptive parent" can be used to refer to either the adoptive mother or the adoptive father.

Definitions of adoptive parent

English

an adult who provides a child a permanent home through a legal procedure in which the court names him or her as the child's legal parent

The process for becoming an adoptive parent is rigorous, as you would expect.