|fu̇rē|ā- noun
Usage: usually capitalized F
Etymology: after Baron Jean Baptiste Joseph Fourier died 1830
mathematics : an infinite series of the form a o /2+ a 1 cos x+b 1 sin x+a 2 cos2 x+b 2 sin2 x+ … that may be used to approximate a function or to fit a given set of data (as periodic data)