(Australia, UK, New Zealand) A length of sawn wood of cross section 4 inches by 2 inches, most often employed as structural framing lumber / timber.

A law student in his or her fourth year of law school; generally an unusual situation occurring where a student has either taken an extended part-time curriculum, or has failed a class needed for graduation and must stay on for an extra semester after the three L year.

Acknowledgment of message received.

The cardinal number occurring after three hundred ninety-nine and before four hundred one, represented in Arabic numerals as 400.

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.

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.

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

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.