ETYM Latin dominans, -antis, p. pr. of dominari: cf. French dominant. Related to Dominate.
1. Exercising influence or control.
2. Of genes; producing the same phenotype whether its allele is identical or dissimilar.

(Music) The fifth note of the diatonic scale.
In music, the fifth note of the diatonic scale, for example, G in the C major scale. The chord of the dominant is related to the tonic chord by the dominant note, which corresponds to its third harmonic. Classical modulation involves a harmonic progression from the tonic to the dominant and back. The return may be a symmetrical journey, as in the binary form of a sonata by Scarlatti, or an abrupt resolution of dominant to tonic chords in a “perfect” cadence.

1. Adominant genetic character or factor.
2. Any of one or more kinds of organism (as a species) in an ecological community that exerts a controlling influence on the environment and thereby largely determines what other kinds of organisms are present.
3. A dominant individual in a social hierarchy.