live-in

Short definition from Wiktionary

Adjective

1. 1
   Living on the premises; usually said of a household employee or a domestic partner.

Noun

1. 1
   A household employee or domestic partner who lives on the premises of the employer or partner.
2. 2
   A firefighter who lives at the fire station.

Verb

1. 1
   To reside on the premises of one's employer (used especially of domestic staff such as nannies, cooks, maids, etc.)
2. 2
   Used other than figuratively or idiomatically: see live, in.