A horse-drawn hackney cab with four wheels, as opposed to a hansom or dogcart. / Any vehicle with four wheels.

A method of encoding Chinese characters using four numerical digits per character (in some situations, an additional digit is used).

(baseball) The sign made by the manager directing the pitcher to issue an intentional walk.

(informal) The Beatles.

measuring two inches by four inches / (by extension) small or cramped

(construction) A length of lumber having a cross section of two inches by four inches, or in the case of dimensional lumber three and a half inches by one and a half inches.

A sport played by four players where players have to hit a ball into other people's squares, and attempt to make a return hit.

(motor vehicles) A four-speed manual transmission whose gearshift lever is mounted beside the driver on the floor of the vehicle.

Alternative form of clue-by-four

Of a plant, having four leaves.