Melanism is an undue development of dark-colored pigment in the skin or its appendages and is the opposite of albinism. It is also the medical term for black jaundice. The word 'melanism' is deduced from the Greek: μελανός, meaning black pigment.
Pseudo-melanism, also called abundism, is another variant of pigmentation, characterized by dark spots or enlarged stripes, which cover a large part of the body of the animal making it appear melanistic. A deficiency in or total absence of melanin pigments is called amelanism.
The morbid deposition of black matter, often of a malignant character, causing pigmented tumors is called melanosis. For a description of melanin-related disorders see melanin, melanosis coli and ocular melanosis.