trans·for·ma·tion 
(trăns′fər-māshən, -fôr-)
(trăns′fər-māshən, -fôr-)n.
1.
a. The act or an instance of transforming: her difficult transformation of the yard into a garden.
b. The state of being transformed: impressed by the transformation of the yard.
2. A marked change, as in appearance or character, usually for the better: recent transformations in the format of the publication.
3. Mathematics
a. Replacement of the variables in an algebraic expression by their values in terms of another set of variables.
b. A mapping of one space onto another or onto itself.
4. Linguistics An operation or rule that changes one linguistic structure (especially a syntactic structure) into another, as by the merger, relocation, or deletion of one of its constituents.
5. Genetics
a. The change undergone by an animal cell upon infection by a cancer-causing virus.
b. The introduction of DNA from one cell into another by means of a bacteriophage or one of a variety of chemical or physical methods.
trans′for·mation·al, trans·forma·tive (-fôrmə-tĭv) adj.