What is the moment when all oscillators aligned to make a jump called? Say we have a square wave and its Fourier series. When the wave doesn't jump, its oscillators aren't aligned:



But if they are aligned, the wave will jump:



What is this moment called? They might not be necessary in the same angle, and I don't think "resonating together" is correct, since they have different frequencies. What is it called when all oscillators aligned to make a jump?



Meta discussion: Why are questions asking for terms off-topic?
I think the word/phrase you are looking for is "discontinuity" / "discontinuity in the source signal".  Although a jump is always a discontinuity, a discontinuity is not always a jump.  When it isn't a jump, it is known as a pluggable discontinuity, i.e. you can define a value to plug a hole.  The sinc function at zero is an example of this.  So to be more specific you would say "an unpluggable discontinuity".

Whether a series of continuous functions could converge to a discontinuous function was a question that led to some very serious, and non-intuitive, math.

As far as I know, there is no word to describe the state of the components at this moment.  The closest word I can think of is a secondary meaning of "concordance" = "agreement".

Hope this helps.

Ced