What does "twelve o'clock" mean?

The start of the thirteenth hour of the day; noon (noontime); 12:00 p.m. (12:00).

What is a synonym for "twelve o'clock"?

Common synonyms include: catalan dotze.

noun, slang

noun, slang ·Uncommon ·College level

Noun

1
The start of the thirteenth hour of the day; noon (noontime); 12:00 p.m. (12:00). uncountable, usually
"The next train comes at twelve o'clock (= "The next train comes at noon")."
2
The start of the first hour of the day; midnight; 12:00 a.m. (00:00). uncountable, usually
"The bar closes at twelve o'clock (= "The bar closes at midnight")."
3
A position straight ahead (horizontal clock orientation) or above (vertical clock orientation) (from the location of the 12 mark on a clock face) informal, uncountable, usually
"We've got a bogey at twelve o'clock (= "We've got a bogey straight in front of us")."

"The next train comes at twelve o'clock (= "The next train comes at noon")."