For a sine wave $x=A\sin(ωt+\varphi)$,

  • $A$ is the amplitude
  • $\omega$ is the frequency
  • $\varphi$ is the phase

What is $(ωt+\varphi)$ called? "Angle"? I can't find any source call that part.


2 Answers 2


$\omega t + \varphi$ is called the phase. See this Wikipedia article for the details.

The symbol $\varphi$ is known variously as the phase shift, phase offset or phase constant.

  • 1
    $\begingroup$ Wikipedia is not an authority on the use is scientific or technical terminology. In common speech, $\varphi$ is called both the "phase" and the "phase offset", and probably other things, all determined by context. It is misleading to claim that there's a universal and consistent use of terms. $\endgroup$
    – DanielSank
    Mar 25, 2018 at 17:00

As with functions in general, the quantity inside $\sin$ here is called an argument.


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