oat

American  

[oht] / oʊt /

noun

1. a cereal grass, Avena sativa, cultivated for its edible seed.

2. (used with a singular or plural verb) Usually oats. the seed of this plant, used as a food for humans and animals.

3. any of several plants of the same genus, as the wild oat.

4. Archaic. a musical pipe made of an oat straw.

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idioms

1. sow one's wild oats. wild oat.

2. feel one's oats,

   1. to feel frisky or lively.

   2. to be aware of and use one's importance or power.

oat British  

/ əʊt /

noun

1. an erect annual grass, Avena sativa, grown in temperate regions for its edible seed

2. (usually plural) the seeds or fruits of this grass

3. any of various other grasses of the genus Avena, such as the wild oat

4. poetic a flute made from an oat straw

5. informal

   1. to feel exuberant

   2. to feel self-important

6. slang to have sexual intercourse

7. to indulge in adventure or promiscuity during youth

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Other Word Forms

• oatlike adjective

Etymology

Origin of oat

before 900; Middle English ote, Old English āte

Explanation

An oat is a cereal grain, the seed of a plant that grows like a tall grass in fields. Your dad might love to bake with oats. You're most likely to see the noun oat in its plural form — oats. Oats are grown for both animal feed and human consumption. If you ever eat oatmeal for breakfast, you know what an oat looks like, at least in its rolled, flake-like form. The Old English root is ate, "grain of the wild oat plant." The source of this word isn't known for sure, though it may come from the Old Norse eitill, "nodule" or "single grain."

Example Sentences

The hottest job perk right now isn’t unlimited paid time off or oat milk in the office kitchen — it’s job security, period.

From MarketWatch • Apr. 7, 2026

Follow up assessments took place immediately after the two day oat phase and again at two, four, and six weeks.

From Science Daily • Feb. 25, 2026

Vegans and vegetarians have popularized plant-based milk alternatives — almond milk, oat milk, soy milk, cashew, hemp, coconut; if it grows, it may have a milk version.

From Los Angeles Times • Feb. 14, 2026

Shoppers are greeted by mood lighting, shiny pears and soft-beige shelves holding $15 glass bottles of oat milk, $15 chicken nuggets and $750 caviar.

From The Wall Street Journal • Feb. 10, 2026

“Hard bread, hard cheese, oat cakes, salt cod, salt beef, salt mutton, and a skin of sweet wine to rinse all that salt out of my mouth. I will not die of hunger.”

From "A Dance with Dragons" by George R. R. Martin