noontime

From noon +‎ time, perhaps an innovation of earlier English noontide (“noontime”), from Middle English noon tijd, from Old English nōntīd (“noontime”). Eclipsed non-native Middle English merian, merion (“noontime”) from Old French meriiene, merīane (“noontime”).

noontime (plural noontimes)

1. Noon.

   Synonym: high noon

2. Approximately noon.

   the noontime hours

3. (figurative) The time at which something peaks in some way (e.g., in vitality, in influence, in reknown) (by analogy with the waxing of the sun each day).
   • 1890, J.W. Collins, “Society proceedings of the Colorado State Medical Society”, in The Omaha Clinic‎, volume 3, number 5, retrieved 2021-03-20, page 131:

     We should so organize our rank and mobilize our forces that our influence may not be dissipated before the advancing hosts of quackery and ignorance. This we can do effectively if only the wise and successful ones among our leaders can be induced to forgo the dolce far niente of the noontime of their lives.

• midday, nones, sext; see also Thesaurus:midday