Nouns That Start With O

The definition of a noun is “a person, place, thing, or idea.” You’ll notice many of them come after an article, like "a," "an," or "the." Nouns commonly act as the subject of a sentence. For example, "The observer saw him push her to the ground."

Nouns can also serve as the object of a sentence. That means they'll come after the verb. For example, "She sliced the orange." Nouns also function as names, including people, cities, and more.

From oafs, to ogres, to onions, enjoy this long list of O-nouns. Perhaps one or two of them will spice up your next writing piece.

1. Oaf - a clumsy person
2. Oasis - a fertile place where there is water in the midst of a desert
3. Oatmeal - oats that are ground into flakes
4. Obedience - the willingness to obey
5. Obesity - the condition of being overweight
6. Object - anything that is visible
7. Obligation - something someone is required to do
8. Oblivion - the state of being forgotten
9. Oblong - a shape, like a rectangle or an ellipse, with one longer end
10. Observer - a person watching something
11. Occupant - one that resides in or uses a physical space
12. Occasion - a special event
13. Ocean - the body of salt water covering much of the Earth
14. Octagon - an eight-sided shape
15. October - the tenth month of the year
16. Octopus - a sea creature with eight sucker-lined limbs
17. Ode - a poem written in a clear, lyrical style
18. Odor - a distinctive and unpleasant smell
19. Offense - something that angers or displeases
20. Offer - an act of putting something forth for consideration
21. Officer - a person in a position of authority in a business, the police, or the military
22. Offshoot - something that derives its origin from a particular source
23. Offspring - a child, or the children of a family
24. Ogre - a giant monster in legends and fairy tales that eats humans
25. Oiliness - the quality of being too slippery or smooth
26. Ointment - a semisolid substance used on the skin as medicine
27. Olive - a small yellow-green fruit, usually eaten cured
28. Omelet - a dish consisting of beaten eggs, seasonings, cheese, or vegetables
29. Omen - something believed to predict the future
30. Omission - the act of leaving something out
31. Omnipotent - one having unlimited or universal power
32. Omnivore - someone or something that eats meats and plants
33. Onion - a plant with an edible bulb
34. Onslaught - a situation where you’re suddenly bombarded with a lot of things at once
35. Ooze - the liquid result of a slow leak or spill
36. Opal - a gemstone made of hydrated silica
37. Openness - an accommodating attitude receptive to new ideas
38. Operation - a surgical procedure
39. Opinion - a belief or judgment held by a person
40. Opportunity - a favorable situation for a positive outcome
41. Opposite - something that is the reverse of something else
42. Oppression - treating people unfairly, especially with overuse of government power
43. Option - the power to make a choice
44. Oral - an exam given and taken by speaking
45. Orange - a round, sweet, juicy citrus fruit
46. Ordinary - an official with jurisdiction in a specified area by right of their office
47. Original - the earliest form of something
48. Ostrich - a swift-running bird of Africa and SW Asia
49. Outcast - a person who doesn’t fit in with the majority and isn’t accepted by the crowd
50. Outlook - how things are looking for the future

Nouns starting with O are far from ordinary, right? Since nouns can pop up all over a sentence, you probably won’t be surprised to learn there are over 10 different types of nouns. If they’re referring to a person or place, they’re likely acting as a proper noun (e.g. Shrek, Oman, California, France, and The Oriental Hotel). An example of that would be, "Shrek is a kind-hearted ogre."

The opposite of a proper noun is a common noun. These nouns refer to general, unspecified things. In the example above, Shrek is a proper noun. But, if that line simply read, "The ogre was kind-hearted," you'd know the subject was a common noun. Common nouns are neither capitalized nor specific.

Then, there are compound nouns (e.g., sunglasses and doorframes), countable nouns, possessive nouns, and pronouns. It’s common to see both nouns and pronouns in a single sentence: "Jennifer ran down the boardwalk to greet her.”

Are you ready to see the letter O hard at work? You’ll be able to see these nouns function as subjects and objects. Notice that many of the nouns are preceded by an article.

Here are 10 sample sentences. Click on the link in each sentence to see more example sentences containing that O-noun:

1. She eats oatmeal every morning for breakfast.
2. We all have an obligation to be nice.
3. If you sit by the ocean, it’ll wash all your worries away.
4. This is an ode to the loss of love.
5. She inherited a grove full of olives in Tuscany.
6. That omission makes you a liar.
7. Let’s cook that steak in garlic and onion.
8. Her engagement ring features a giant opal.
9. We will ban any type of oppression.
10. She is far from ordinary.

Nouns are just the beginning when it comes to words that begin with O. If you're open to going beyond nouns, you'll be excited to discover this list of words that start with O on WordFinder by YourDictionary. Form a full list of O-words organized by length to an easy-to-use search feature that allows you to limit the results to words of a certain length or terms that start, conclude or include specific letters or combinations of letters. Exploring this list provides a great opportunity to explore the full spectrum of O-words in the English language.

The more we read, the more we open our minds to magic. With one flip of the page, we can venture off to unknown worlds filled with mythical dragons, fairy princesses, and ugly ogres. Thanks to literature and poetry, a passport isn’t required to enter new realms. The further you escape into fantasy, the more your vocabulary will grow. Ready to dabble in a little writing yourself? Scan through these nouns that start with N to see if you can fancify your next tale with any of these nuanced nouns.