noon
noun /nuːn/
  /nuːn/
[uncountable]Idioms - 12 o’clock in the middle of the day synonym midday- We should be there by noon.
- The conference opens at 12 noon on Saturday.
- the noon deadline for the end of hostilities
- I'm leaving on the noon train.
 Oxford Collocations Dictionaryadjective- 12
- high
 - around noon
- at noon
- by noon
- …
 - morning, noon and night
 Word OriginOld English nōn ‘the ninth hour from sunrise, i.e. approximately 3 p.m.’, from Latin nona (hora) ‘ninth hour’.
Idioms 
morning, noon and night 
- at all times of the day and night (used to emphasize that something happens very often or that it happens continuously)- She talks about him morning, noon and night.
- The work continues morning, noon and night.
- It's all she talks about, morning, noon and night.