oh

exclamation10

1. •
   showing that the speaker is surprised by something

   • Oh! I didn't see you there.
2. •
   Expression of wonder, amazement, or awe.

   • Oh, wow! That's amazing.
3. •
   Expression of understanding, affirmation, recognition, or realization.

   • Oh, so that's how it works.
4. •
   A word to precede an added or offhand comment or afterthought.

   • Oh, and don't forget your coat.
   • What if he says, "Oh, I need to see your ID"?
5. •
   A word to precede an annoyed remark.

   • Oh, leave me alone.
6. •
   Expression of mild scepticism.

   • "You should watch where you're going!" "Oh?"
7. •
   Exclamation for drama or emphasis.

   • Oh, when will it end?
8. •
   Expression of pain. See ouch.

   • Oh! That hurt.
9. •
   An invocation or address (similar to the vocative in languages with noun declension), often with a term of endearment.

   • Oh, gosh.
10. •
    Space filler or extra syllable, especially in (popular) music.

    • I'm off with the raggle-taggle gypsy-oh. — 1968

noun3

1. •
   An utterance of oh; a spoken expression of surprise, acknowledgement, etc.

   • There were ohs and ahs, and the people twisted about as they looked for her. Then they began to applaud. — 2011
2. •
   The digit 0 (especially in representations of speech)

   • "Oh-dark-thirty," the first soldier muttered without looking at his watch. — 2015
3. •
   The name of the Latin script letter O/o.

   • One genuine recycled local glass of aitch-two-oh — 2006

verb1

1. •
   To utter the interjection oh; to express surprise, etc.

noun5

1. •
   Abbreviation of Ohio: a state of the United States.
2. •
   (Internet) Initialism of other half: a husband, wife, partner, etc.
3. •
   [plural only] Initialism of office hours.
4. •
   (Internet) Initialism of overheard; a post whose contents were overheard by its author.

   • OH: "We should just burn the whole place down"
5. •
   (US) Initialism of observation helicopter.