Definition of noon :
1. Belonging to midday; occurring at midday; meridional.
2. Hence, the highest point; culmination.
3. No. See the Note under No.
4. Of or pertaining to noon; meridional; as, the midday sun.
5. The middle of the day; midday; the time when the sun is in the meridian; twelve o'clock in the daytime.
6. To take rest and refreshment at noon.
high tide, sum, crest, lunchtime, culmination, noontime, apogee, tip-top, crescendo, time, acme, ne plus ultra, capstone, climax, noon hour, twelve noon, high-water mark, the forenoon, pinnacle, zenith, lunch time, high noon, peak, apex, head, crown, cockcrow, drivetime, top, summit, first light
day (part of speech: noun)