1.AdverbIn actual use or existence, regardless of official or legal status.
2.AdjectiveIn actual use or existence, regardless of official or legal status.
"While it is largely recognized that Ukraine holds de jure sovereignty on Crimea, Russia exercises de facto administration on the peninsula."
3.NounA legally undeclared spouse; a partner in a spousal relationship which is not officially declared as a marriage, comparable to a common law husband or wife.