The difference between Defiant and Dominant

When used as adjectives, defiant means defying, whereas dominant means ruling.

Dominant is also noun with the meaning: the fifth major tone of a musical scale (five major steps above the note in question).

check bellow for the other definitions of Defiant and Dominant

Dominant as a noun (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.
Dominant as a noun (music):

The triad built on the dominant tone.
Dominant as a noun (genetics):

A gene that is dominant.
Dominant as a noun:

A species or organism that is dominant.
Dominant as a noun (BDSM):

The dominating partner in sadomasochistic sexual activity.

Dominant as an adjective:

Ruling; governing; prevailing

Examples:

"The dominant party controlled the government."
Dominant as an adjective:

Predominant, common, prevalent, of greatest importance.

Examples:

"The dominant plants of the Carboniferous were lycopods and early conifers."
Dominant as an adjective (medicine):

Designating the follicle which will survive atresia and permit ovulation.