The definition of adoption, at its most basic, is to legally take parental responsibility of a child and raise it as if one's own. It seems simple enough, right? Easier said than done, perhaps. Before the ends of adoption, which is what the above definition refers to, is the means of an adoption. And the adoption process is what makes the entire adoption community so vibrant and rich with people from all walks of life.
There are varying degrees of relationships a child will have with his or her adoptive parents and birth relatives. There are adoptions that involve surrogate mothers, relatives, stepparents and those that include sibling sets. There are international adoptions, independent adoptions and public and private agency adoptions. There is infant adoption, and within those, there are open, semi-open and closed adoptions. There are adoptions between states, called interstate adoptions. There is the adoption of foster children through public agencies or fost-adopt and legal risk programs.
Relatively speaking, the adoption process is such a small part of the adoption definition that it doesn't make much more than an implication in the word "legal." The events that brought you to consider adoption, the process of being placed with your future child, the negotiations, travel and finalization are all simply part of the "legal" side of adoption. The actual definition hinges on the verb "raise." Because that's what adoption is: raising a child that is not biologically related to you.