noun

• A transformation, such as one performed by magic.
• A noticeable change in character, appearance, function or condition.
• (biology) A change in the form and often habits of an animal after the embryonic stage during normal development. (e.g. the transformation of a caterpillar into a butterfly or a tadpole into a frog.)
• (pathology) A change in the structure of a specific body tissue. Usually degenerative.