• Sexual dimorphism, differences in the body appearance of a species based on sex
• Nuclear dimorphism, when a cell's nuclear apparatus is composed of two structurally and functionally differentiated types of nuclei
• Phenotypic switching, switching between two cell-types. For example the fungus Candida albicans infects host tissue by switching from its usual unicellular yeast-like form into an invasive, multicellular filamentous form
• Frond dimorphism, differing forms of fern fronds between the sterile and fertile fronds

See also

• Polymorphism