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?