What does "noonday" mean?

The time of noon; the time of day when the sun is highest in the sky, especially on a hot day.

What is a synonym for "noonday"?

Common synonyms include: midday, noon, noontime, high noon, meridian, noontide.

/ˈnundeɪ/ noun

noun ·Rare ·Advanced level

Noun

1
The time of noon; the time of day when the sun is highest in the sky, especially on a hot day. countable, uncountable
"She should not walk, he said, through the dust and heat of the noonday; Nay, she should ride like a queen, not plod along like a peasant."
2
the middle of the day wordnet
3
The time of greatest prosperity. countable, figuratively, uncountable

"The noonday sun beat down with dazzling brightness on the tennis court."

From noon + day.