metaplasia

Normal transformation of tissue from one type to another, as in the ossification of cartilage to form bone.

Transformation of cells from a normal to an abnormal state.

The conversion of an adult tissue directly into another form of adult tissue, as of hyaline cartilage into mucous tissue. This takes place principally, if not exclusively, among the tissues of the connective-tissue group.

the conversion of one type of tissue into another