often attributive
1
a
: any of several grasses (genus Avena)
especially : a widely cultivated cereal grass (A. sativa)
b
: a crop or plot of the oat
also : the seed of an oat
usually used in plural but singular or plural in construction
2
archaic : a reed instrument made of an oat straw

Illustration of oat

Illustration of oat
  • oat 1a
Phrases
feel one's oats
: to act in a newly self-confident and often self-important manner

Examples of oat in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Protein Mug Cake A protein mug cake is a high-protein dessert made with oat flour that may satisfy sweet cravings. Lauren Panoff, Verywell Health, 20 Oct. 2025 The seven rooms have white and oat-colored linens and raffia lampshades, and many have freestanding tubs. Sophie Friedman, AFAR Media, 18 Oct. 2025 Overnight Oats Overnight oats are easy to prepare and high in a kind of soluble fiber called beta-glucan, which may lower heart disease risk factors like high cholesterol and blood pressure. Jillian Kubala, Health, 17 Oct. 2025 They’re filled with gooey peanut butter chips, chocolate chips, and crunchy walnuts, mixed together in a deliciously chewy oat batter. Sophia Beams, Better Homes & Gardens, 11 Oct. 2025 See All Example Sentences for oat

Word History

Etymology

Middle English ote "the grain of the oat plant, the plant itself," going back to Old English āte (weak feminine noun), of uncertain origin

Note: Old English āte has been compared with regional Dutch aate, oote "wild oats" (West and Zeeland Flanders), West Frisian and Groningen Dutch oat. (These contrast with Dutch haver, denoting cultivated oats, a reflex of the Common Germanic word for the grain.) Michiel de Vaan, in an addenda to the online etymologiebank.nl, believes that the Flanders words are semantic extensions of regional aat "food," of general Germanic origin (see eat entry 2), though this hypothesis would scarcely explain the Old English word. Jan de Vries (Nederlands Etymologisch Woordenboek, Brill, 1971) hypothesizes that the Low Country words may have been borrowed from English.

First Known Use

before the 12th century, in the meaning defined at sense 1a

Time Traveler
The first known use of oat was before the 12th century

Browse Nearby Words

Cite this Entry

“Oat.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/oat. Accessed 22 Oct. 2025.

Kids Definition

oat

noun
: a grain that is widely grown for its long loose clusters of seeds which are used for human food and for livestock feed
oaten
ˈōt-ᵊn
adjective

More from Merriam-Webster on oat

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!