Updated: 12/31/2022 by Computer Hope

O may refer to any of the following:

1. The letter "o" is chat slang for "oh."

2. O is a keyboard key used with the keyboard shortcuts Alt+O, Command+O, and Ctrl+O.

Letter O and Zero (0)

3. The letter "O" is sometimes confused with the number zero (0). To help differentiate between an "o" and a zero, a zero may have a dot or a forward slash. Showing the zero this way helps the reader quickly identify numbers from letters. For example, looking at the picture, you can quickly identify the zero in the "COMPUTER H0PE" text. However, in the font used here, the "0" is not as easy to notice.

4. With Microsoft Excel and other spreadsheet programs, "O" is the fifteenth column of a spreadsheet. To reference the first cell in the column, you'd use "O1."

5. In Adobe Photoshop, O is a shortcut to select dodge, burn, and sponge tools. Holding down the Shift while pressing O cycles through all options.

6. In the phonetic alphabet, "O" is often pronounced as "Oscar."

7. O is the fifteenth letter of the English alphabet. The letter "O" comes after "N" and is followed by the letter "P." To create a capitalized "O," press Shift and O at the same time.

With U.S. QWERTY keyboards, the "O" key is on the top row, to the right of "I" and left of the "P" key. See our keyboard page for a visual example of all keyboard keys.


If the "O" key is not working on the keyboard, see: Some keys on my computer keyboard aren't working.


In ASCII (American Standard Code for Information Interchange), the uppercase "O" is "079" in decimal (01001111 in binary). The lowercase "o" is "111" in decimal (01101111 in binary).


Doing the Alt code Alt+79 creates a capital "O," and Alt+111 creates a lowercase "o" character.


The number 6 on a phone keypad creates an "O" on a US phone.

Chat terms, Computer abbreviations, Letter