What does the P stand for on money?

Answer 1

It's not clear what you're referring to, but if you're describing the small letters "P" and "D" on current US circulating coins, they're called mintmarks.

A mintmark (also spelled mint mark) is a letter or symbol that tells where a coin was produced, or "minted". Knowing where to look for a mintmark and what it means can sometimes be confusing. The US practice is to use a one- or two-letter abbreviation for the city where a mint is located, but other countries use symbols, sequential lettering, or other indicators.

"P" on a modern coin indicates it was struck at the Philadelphia Mint. Other letters are D indicates Denver, S San Francisco, and a W indicates West Point (commemorative coins only). Also, with the exception of certain WWII-era nickels and 1979 $1 coins, Philadelphia coins minted before 1980 do not have mintmarks.

Older coins may have an O (New Orleans), CC (Carson City), C (Charlotte) or D (Dahlonega, GA long before Denver opened)