commonly or generally known or seen

a familiar sight.

well-acquainted; thoroughly conversant

to be familiar with a subject.

informal; easygoing; unceremonious; unconstrained

to write in a familiar style.

closely intimate or personal

a familiar friend; to be on familiar terms.

unduly intimate; too personal; taking liberties; presuming

The duchess disliked familiar servants.

domesticated; tame.

of or pertaining to a family or household.

a familiar friend or associate.

Witchcraft and Demonology .

an animal, as a cat, that embodies a supernatural spirit and aids a witch in performing magic.

familiar spirit.

Roman Catholic Church .

an officer of the Inquisition, employed to arrest accused or suspected persons.

a person who belongs to the household of the pope or of a bishop, rendering domestic though not menial service.