Definition of: noon

(nn) noun
1. That time of day when the sun is on the meridian; the middle of the day; in an exact sense, 12 o'clock in the daytime.
2. The highest point of any period or career: the noon of life.
3. Originally, the ninth hour after sunrise, or about 3 o'clock p.m; midway between 12 o'clock and sunset; hence, the canonical hour of nones.
4. plural A noontime repast. [OE non <L nona (hora) ninth (hour)]