# Terminology: Alternatives for zero crossing

Is it correct to name the red and blue points hinge points, as an alternative to zero crossing? Or are their better terms to describe these points?

Update

I have several functions like these. I want to stress that these points are 'fixed', and not the fact they cross zero.

• Points $x$ such that $f(x) = 0$ are called zeros of $f$, or roots of $f = 0$ or the $0$-level set of $f$. Haven't heard of hinge points – Ilya Jul 24 '14 at 10:31
• It sounds like "hinge points" might be another name for what I know as "turning points", which are where $f''(x)=0$. In the graphic above, it looks like the red and blue points are turning points and zeroes. – Matt R. Jul 24 '14 at 10:36
• Zero crossing seems like a perfectly adequate term (even preferred I would say). Is there any reason you don't want to use it? – EuYu Jul 24 '14 at 10:41
• Turning point is another term for inflection point. – traindriver Jul 24 '14 at 10:42
• I suggest "pivot point". Which I suppose means the same as hinge point, but it sounds more technical :-) – TonyK Jul 24 '14 at 10:46

If $f$ is a real or complex valued function and $x$ is the point for which $f(x) = 0$, the usual terminology is to say that $x$ is the root of $f$.