to increase to four times as much; to multiply by four

(mathematics) An algebraic variety of degree 4.

(US, education) The period in school that comes after third grade and before fifth grade.

(mathematics) A mathematical operation that transforms a function for a discrete or continuous spectrum into a function for the amplitude with the given spectrum; an inverse transform of the Fourier transform.

A member of a certain family of algorithms for efficiently computing the discrete Fourier transform of data. / An instance of performing one of these algorithms.

(idiomatic, US) Demonstratively patriotic about the United States.

Hypothetical resurrection of the Third Reich. / (historical) Nickname for Washington Heights, Manhattan, after the German immigrants there.

(American football) The fourth down in a series that has a maximum of four downs; often used to punt the ball downfield or attempt a field goal (If not punted or converted, the opposing team takes possession wherever the ball is).

A species of fish of the Cottidae family, Myoxocephalus quadricornis, found in Canada, Finland, Greenland, Norway, Russia, Sweden, and the United States.

plural of fourhorn sculpin