Dominance in the context of biology and anthropology is the state of having high social status relative to other individuals, who react submissively to dominant individuals. The opposite of dominance is submissiveness.
Dominance or domination, in terms of BDSM, refers to taking control of a person or situation through usage of some means (physical, mental, financial, and so forth), or to exercise this power. A person who exercises this power on a regular basis, outside of BDSM scenes, is called a Dominant; the gender specific titles being Dom for a man, Domme or Dominatrix for a woman. See domination and submission for more information.
"Dominance hierarchies" are found in many animals, including primates such as human beings.
A cadential dominant chord followed by a tonic chord (the chord of the key of the piece) produces an authentic cadence.
Modulation into the dominant key often creates a sense of increased tension; as opposed to modulation into subdominant (fourth note of the scale), which creates a sense of musical relaxation (because the tonic key is the dominant of its subdominant key: in F major, the dominant is C).
The dominant may also be considered the result of a transformational operation applied to the tonic that most closely resembles the tonic by some clear-cut criteria such as common tones (Perle 1955 cited in Wilson 1992, p.37-38).