The middle of the day; midday; the time when the sun is in the meridian; twelve o'clock in the daytime.

Belonging to midday; occurring at midday; meridional.

The instant at which a time reference is over the upper branch of the reference meridian. Noon may be solar or sidereal as either the sun or vernal equinox is over the upper branch of the reference meridian. Solar noon may be further classified as mean or apparent as the mean or apparent sun is the reference. Noon may also be classified according to the reference meridian, either the local or Greenwich meridian or additionally in the case of mean noon, a designated time zone meridian.

the middle of the daylight period; 180 degrees from midnight. Where a.m. ends and p.m. begins.

and midnight: use those words wherever possible to eliminate confusion. If numbers are required, noon is generally agreed to be 12:00 p.m. and midnight 12:00 a.m. (for 24-hour time, these would be 1200 and 2400). Within a printed or web document, be consistent by using only one format. In e-mail, it is OK to use the abbreviated format in the subject line, and then use the standard format in the body.

Hence, the highest point; culmination.

To take rest and refreshment at noon.

No. See the Note under No.