Dominant

Dominant is an adjective meaning commanding, governing, or having power or influence over others. It is used to describe something that is most important, prominent, or controlling within a system. In genetics and heredity, dominant refers to an allele or trait that can express itself in an organism even when only one copy is present. A dominant allele masks the effect of a recessive allele in a heterozygous individual; recessive traits require two copies to be expressed. Not all genes show clear dominance; incomplete dominance and codominance are alternative patterns in which alleles interact differently, producing intermediate or combined phenotypes. For example, ABO blood group alleles IA and IB are codominant with each other, while the i allele is recessive to both.

In behavioral and social contexts, dominance describes an individual's or group's relative power, influence, or control within a hierarchy. Dominance can emerge through age, size, aggression, signaling, or social experience and may shift with context and over time. In many animal species, dominance hierarchies organize access to resources; in humans, the term is used in sociology, anthropology, and organizational studies to discuss power relations and leadership.

In music theory, the dominant is the fifth scale degree of a diatonic scale and the chord built on it. The dominant degree creates tension that typically resolves to the tonic, shaping musical phrasing.

In game theory and economics, a dominant strategy is one that yields a higher payoff regardless of other players' choices.

Note on usage: the term can also describe the prevailing culture, species, or language in a given setting. The word derives from Latin dominans, present participle of dominārī, meaning to rule.