Definition:Fourier Series/Also known as

Fourier Series: Also known as
The Fourier series, as defined on the general open interval $\openint \alpha {\alpha + 2 \lambda}$, can often be seen referred to as the whole-range Fourier series.

This is in order to distinguish it from the $2$ varieties of half-range Fourier series, which are applied to the open interval $\openint 0 \lambda$.