(Applied?) maths terminology question:
In the context of signal analysis (doing things like Fourier transforms) you might have some variable (say, t) that you're treating as being equivalent to time and you're interested in some periodic function of t (say, sin(t)) with wavelength 2pi on the t scale.
It's common to (informally?) use the term "phase" to refer to the value of t within the first cycle of the periodic function. In that usage: phase = t modulo 2pi
By extension, I have seen people refer to location anywhere on t (not just the first cycle) as "phase", but this seems to me to be ambiguous, and not necessarily helpful, terminology.
My question is: Given that the variable t is possibly something much more abstract and not necessarily "time", is there some accepted terminology for referring to the variable t in this context?
(This is possibly a non-issue for pure mathematicians because they might never talk about phase and use only symbolic representations without using descriptive words. If so, I would be seeking terminology from some applied discipline where this kind of generic descriptive labelling is used.)
In brief, if I wanted to say:
phase = x modulo 2pi
because I am talking about periodic functions of x, is there some generic descriptive term for variables like x (e.g. time-like)?