The inside of the letter O was not blue, but black.

The use of the letter "O" comes from the original name for this level, "operational immediate".

The number 0 and the letter O are both round, so what is the difference?

Get more information on passports topics that start with the letter "O"

Observers wore a single wing attached directly to the letter "O".

The letter 'o' is often replaced with the numeral 0.

He was especially fond of animal names and added the letter "o" to Elk.

Bob places a letter "O" under her fingernails, as he had done with other letters on past victims.

His mouth was open and was probably forming the letter "o".

The letter 'o' is one of the most used in the English language.