Ruling; governing; prevailing / Predominant, common, prevalent, of greatest importance.

Control by means of superior ability, influence, position, or resources; prevailing force. / The exercise of power in ruling; sovereignty; authority; government.

(music) The fifth major tone of a musical scale (five major steps above the note in question); thus G is the dominant of C, A of D, and so on. / (music) The triad built on the dominant tone.

To govern, rule or control by superior authority or power / To exert an overwhelming guiding influence over something or someone / To enjoy a commanding position in some field

Dominant.

(historical) The late period of the Roman Empire, following the principate, during which the emperor's rule became more explicitly autocratic and remaining vestiges of the Roman Republic were removed from the formal workings of government; the reign of any particular emperor during this period.

present participle of domineer

overbearing, dictatorial or authoritarian

The act of one who domineers.

The state of being dominant; of prime importance; supremacy. / Being in a position of power, authority or ascendancy over others.