the replacement of normal cells by abnormal cells, as in cancer
Word origin
[hetero- + -plasia]hetero- is a combining form meaning “different,” “other,” used in the formation of compoundwords. Other words that use the affix hetero- include: heteroclite, heterocyclic, heterodyne, heterogony, heterography; -plasia is a combining form with the meaning “growth, cellular multiplication,” of the kindspecified by the initial element. Other words that use the affix -plasia include: achondroplasia, aplasia, cataplasia, dysplasia, metaplasia