What is the plural of o?

Answer 1

Suggested styles vary. The usual way to indicate the plural of a letter is by using the uppercase and adding a lowercase S, so it becomes Os. If the context is not clear, some guides allow using the apostrophe S (which should not be used to form other plurals), creating the style O's. There is a third style that uses the English practice of adding -es to some words ending in O, which creates the plural "oes" (this is not widely used).

Example: There are two Gs and two Os in the word Google.

Example: How many I's and how many O's are in the name Pinocchio?