dinner jacket

British term for a standard man's business or formal suit — the kind with matching jacket and trousers worn to weddings, job interviews, and anywhere the dress code reads 'smart'. The 'lounge' part harks back to when a lounge suit was the informal alternative to white tie or morning dress, but over the decades it became the default formal outfit for most occasions. Still seen on wedding invitations instructing guests on appropriate attire, it carries a very particular flavour of British social formality.

A piece of a person's suit, beside trousers and, sometimes, waistcoat; coat (US).

(British) A man’s suit.

(British) A type of thick jacket, usually dark blue, often worn by men who work outside (though originally worn by donkeymen).