The noun Domme is a pseudo-French female variation of the term Dom, which is a shortened version of the word dominant. There is confusion on its pronunciation, with most preferring a pronunciation identical to Dom, by analogy to one-syllable French-derived words like femme or blonde. Some others have assumed the word is an amalgamation of the words "do me" and pronounce it accordingly, while others pronounce the final e as a second syllable, e.g. saying dom-MAY or DOM-may.
An alternate word also used as a feminine of Dom is Domina which is directly from Latin for mistress (woman in charge).
Someone who likes sometimes to be a Domme and sometimes to be a sub is called a Switch.
See the gender-neutral term Dom for information on the role of a Domme or Domina.