Fourier

Fourier may refer to:


 * Fourier (surname), French surname

Mathematics

 * Fourier series, a weighted sum of sinusoids having a common period, the result of Fourier analysis of a periodic function
 * Fourier analysis, the description of functions as sums of sinusoids
 * Fourier transform, the type of linear canonical transform that is the generalization of the Fourier series
 * Fourier operator, the kernel of the Fredholm integral of the first kind that defines the continuous Fourier transform
 * Fourier inversion theorem, any one of several theorems by which Fourier inversion recovers a function from its Fourier transform
 * Short-time Fourier transform or short-term Fourier transform (STFT), a Fourier transform during a short term of time, used in the area of signal analysis
 * Fractional Fourier transform (FRFT), a linear transformation generalizing the Fourier transform, used in the area of harmonic analysis
 * Discrete-time Fourier transform (DTFT), the reverse of the Fourier series, a special case of the Z-transform around the unit circle in the complex plane
 * Discrete Fourier transform (DFT), occasionally called the finite Fourier transform, the Fourier transform of a discrete periodic sequence (yielding discrete periodic frequencies), which can also be thought of as the DTFT of a finite-length sequence evaluated at discrete frequencies
 * Fast Fourier transform (FFT), a fast algorithm for computing a discrete Fourier transform
 * Generalized Fourier series, generalizations of Fourier series that are special cases of decompositions over an orthonormal basis of an inner product space

In physics and engineering

 * The Fourier number ($$\mathit{Fo}$$) (also known as the Fourier modulus), a ratio $$\alpha t/d^2$$ of the rate of heat conduction $$\alpha t$$ to the rate of thermal energy storage $$d^2$$
 * Fourier-transform spectroscopy, a measurement technique whereby spectra are collected based on measurements of the temporal coherence of a radiative source