생물 분류학에서 변종의 아래 단계로, 색상 변이와 같이 사소하거나 일시적인 특징 차이를 보이는 개체군을 나타내는 단위.
A taxonomic category that ranks below variety, which contains organisms differing from the typical kind in some trivial, frequently impermanent, character, such as a color variant.
예문:
"The botanist identified the red-leafed specimen as a new forma of the species."
"In biological nomenclature, a forma is used for minor variations that do not warrant a higher rank."