morph

A sequence of phonemes, often a word fragment, which constitutes the minimum unit of meaning or syntax within a given word. A morph may be one of several variants of a morpheme, depending for its individal form on the context in which it occurs. Thus the morphs -s and -es are variants of the morpheme by which the plural form of an English noun is expressed.(Linguistics)

To transform smoothly in imperceptible steps from one image to another, on a computer screen.