As a Noun: 1. The process by which a child is taken into a family to which it is not biologically related and legally made a son or daughter of that family. English = adoption. 2. A child who has been taken into a family to which it is not biologically related and legally made a son or daughter. As a Verb or Adjective: 1. To take a child into your own family and make it legally your son or daughter. English = adopt. 2. To be taken into a family to which you are not biologically related and to be legally made a son or daughter of that family. English = (be) adopted.