What is the origin of 'sleep tight'?
Read moreOne of the mysteries of the English language finally explained.
A black taxicab; (now usually) (British) a type of taxi, originally and usually (but now not always) black, which may be hailed in the street and can accommodate up to five passengers in the rear, separated from the driver's seat by a partition (officially called Hackney cab).
Early 20th century; earliest use found in Cosmopolitan.