The word lady is a term of respect for a woman, the equivalent of gentleman. Once used to describe only women of a high social class or status, now it may refer to any adult woman. Informal use of this word is sometimes euphemistic ("lady of the night" for a prostitute) or, in American slang, condescending (equivalent to "mister"). "Lady" is also a formal title in the United Kingdom. "Lady" is used before the family name of a woman with a title of nobility or honorary title suo jure (in her own right), or the wife of a lord, a baronet, laird, or a knight, and also before the first name of the daughter of a duke, marquess, or earl.