Harmonic(?) sine and its abbreviation

Question

(I'm not sure about the adjective “harmonic” — maybe it was another one.)

Some years ago I read about harmonic sine function (or sine harmonic one) — probably in some physics textbook — where it was written that it's so common in (some part of physics) that it has its own name (harmonic sine?) and abbreviation.

I'm not able to remember the title of this book, not to find it in Internet and other sources.

I suspect that it was the function $\sin\frac1x$, or the function $x\sin\frac1x$, but I'm not sure.

What is that function, and what are its name and abbreviation?

Answer 1

Perhaps it is the sinc function. The Wikipedia article states:

It was introduced by Philip M. Woodward in his 1952 paper "Information theory and inverse probability in telecommunication", in which he said the function "occurs so often in Fourier analysis and its applications that it does seem to merit some notation of its own",[3] and his 1953 book Probability and Information Theory, with Applications to Radar.[2][4]