O vs Oh - What's the Difference

The English language can be complicated, confusing and even crazy. I have trouble remembering that difference between “O” and “Oh” and when and how to use each of them correctly.

According to Dictionary.com: “O” can be an interjection or a noun.

interjection

• 1. (used before a name in direct address, especially in solemn or poetic language, to lend earnestness to an appeal): Hear, O Israel!
• 2. (used as an expression of surprise, pain, annoyance, longing, gladness, etc.)

noun, plural O’s.

• 3. the exclamation “O.”.

On the other hand: “Oh” can be an interjection, noun or verb.

interjection

• 1. (used as an expression of surprise, pain, disapprobation, etc.)
• 2. (used in direct address to attract the attention of the person spoken to): Oh, John, will you take these books?

noun, plural oh’s, ohs.

• 3. the exclamation “oh.”.

verb (used without object)

• 4. to utter or exclaim “oh.”.

In What’s the Difference Between “O” and “Oh”? at Mental Floss linguist Arika Okrent explains it in greater detail.

“O” may seem like just an old fashioned way to write “Oh,” but it actually has a slightly different meaning. Consider some other famous O’s: O Captain, my captain, O Pioneers, O Come All Ye Faithful, O Canada, O Brother Where Art Thou, O ye of little faith, O Christmas Tree. These are all examples of what’s known as the vocative O—it indicates that someone or something is being directly addressed.

“Oh” has a wider range. It can indicate pain, surprise, disappointment, or really any emotional state...The convention now is that while “oh” can be lower case, and is usually followed by a comma, “O” is always uppercase and without a comma.

In the end she suggests there isn’t much difference, writing: “But there hasn’t always been a strict separation between the two forms. ‘Oh’ and ‘O’ were used interchangeably for a long time. The meanings often overlap too.” Maybe if we remember to reserve “O” for direct address we’ll skate by OK!