O

O is the fifteenth (number 15) letter in the English alphabet and it has a shape of a circle.

It appears after “N” and before “P”.

• On calendars, O sometimes means the month October.
• In chemistry, O represents the symbol "oxygen".
• In medicine, O is one of the human blood types.
• Sometimes when saying decimals, O is another word for 0.

The dictionary definition of o at Wiktionary
Media related to O at Wikimedia Commons