- polymorphism, pleomorphism - (chemistry) the existence of different kinds of crystal of the same chemical compound
 --1 is a kind of chemical phenomenon
 --1 has particulars: dimorphism
- polymorphism - (biology) the existence of two or more forms of individuals within the same animal species (independent of sex differences)
 --2 is a kind of organic phenomenon
 --2 has particulars: dimorphism