Original: With 12-hour time notation, most authorities recommend avoiding confusion by using "noon," "12 noon," or "12:00 noon."
Simplified: Noon is the time exactly halfway through the day, written 12.00 or 12:00 in the 24-hour clock and 12:00 pm in the 12-hour clock. Midday also means noon, although this also means around noon, or very early afternoon.