A bag whose contents are unknown. / A surprise package randomly picked, a lucky dip. / A non-specific mixed lot of a product at the supplier's choice.

(now Australia, slang) A sausage. / (Australia, slang) A pie.

(dated, boats) One of the secret British Q-ships, also known as "decoy vessels" or "special service ships", which served as submarine decoy vessels during World War I.

Someone hired by a company to pose as a customer in order to evaluate the quality of its service.

(Britain) A short-duration outing by coach to a destination that is not revealed in advance

plural of mystery shopper

plural of mystery meat

(informal, derogatory) Any processed meat product whose animal source is not readily identifiable.

(performing arts) A medieval dramatic performance depicting events from Christian scriptures, especially events from the life of Jesus Christ.

plural of mystery play