For non-distorted time zones, when the clock strikes 12 everyone can look up and say that the sun is roughly closest to 12.
If we were too literal with this definition, 12 would even change everyday because of the analemma [1].
[1] https://en.m.wikipedia.org/wiki/Analemma
For non-distorted time zones, when the clock strikes 12 everyone can look up and say that the sun is roughly closest to 12.