In biology, transformation is the uptake of 'naked' DNA into a cell thereby altering the cell genotype of a prokaryote or eukaryote; one of the three modes of gene transfer.

In geometry, a transformation is a change to an object due to a process such as rotation, reflection, enlargement, or translation. In algebra, a transformation is the action of a function; in other words, what happens when there is a one-to-one mapping between sets of objects.