Fourier transformn. An operation that maps a function to its corresponding Fourier series or to an analogous continuous frequency distribution.[After Baron Jean Baptiste Joseph Fourier.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.Fourier transform n (Mathematics) an integral transform, used in many branches of science, of the form F(x) = [1/?(2?)]?eixyf(y)dy, where the limits of integration are from ?? to +? and the function F is the transform of the function f Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014