No, it means noon, or a time period around noon, usually from about 11am until 1pm.

Not quite. 12pm = Noon = Midday (ie. Middle + day) Any time after noon is called...afternoon!

Midday = 12pm. It can be used around that time. Forenoon = before Midday [we usually use "morning"] Afternoon = after Midday When forenoon/morning starts and afternoon ends is a different question. :D