Word
Phenotype
An organism's observable traits, produced through the interaction of its genetic makeup and its environment.
Examples
Leaf size is part of a plant's phenotype.
Two plants can differ in phenotype even when their inherited makeup is very similar.
Origin
The Danish botanist Wilhelm Johannsen introduced phenotype alongside genotype into the vocabulary of heredity in 1909. Phenotype describes observed traits; genotype describes genetic makeup.
How it connects
Phenotype names the outcome we observe rather than a complete explanation of its causes.
This word appeared in What you see is an outcome, the Involves connection for November 2, 2026, which asked: Why doesn't a visible difference tell you what caused it?
Check yourself
Which is a phenotype?
The measured height of a bean plant. Exactly. A measured trait is phenotypic; genotype refers to genetic makeup, while environmental inputs help shape the result.
What the sources establish
Phenotype refers to observable traits influenced by genotype and environment; Johannsen established the genotype–phenotype distinction.
Sources
Phenotype (National Human Genome Research Institute), Definition and narration: observable traits, genotype, and environment
1909: The Word Gene Coined (National Human Genome Research Institute), Johannsen's distinction between phenotype and genotype