What does "cohabit" mean?

Cohabit: To dwell or live together as husband and wife. The law presumes that husband and wife cohabit together, even after a voluntary separation has taken place between them. Bouvier. Note: By the common law as existing in the United States, marriage is presumed when a man and woman cohabit permanently together, being reputed by those who know them to be husband and wife, and admitting the relationship. Wharton.