acorn

noun

ˈā-ˌkȯrn  -kərn 

: the nut of the oak usually seated in or surrounded by a hard woody cupule of indurated bracts

Illustration of acorn

Examples of acorn in a Sentence

Recent Examples on the Web

In addition, mature oaks produce acorn crops regularly, which are a favorite food of many kinds of wildlife. —Arricca Elin Sansone, Southern Living, 3 Sep. 2025

This nut gather is easy to use and lightweight, making quick work of annoying nuts and acorns. —Christopher Murray May Earn A Commission If You Buy Through Our Referral Links. This Content Was Created By A Team That Works Independently From The Fox Newsroom., FOXNews.com, 2 Sep. 2025

The idea of Matos actually sustaining his hot streak is more than a baseball acorn to dig out of the winter tundra. —Grant Brisbee, New York Times, 25 Aug. 2025

The gray hoards his food, making caches of acorns and other nuts or burying them in the ground. —Charles Elliott, Outdoor Life, 21 Aug. 2025

Word History

Etymology

Middle English akorn, akkorn (partially assimilated to corn "kernel, corn entry 1"), hakerne, accherne, accharne, going back to Old English æcern, going back to Germanic *akrana- (whence also Middle High German ackeran "tree nuts," Old Norse akarn, Gothic akran "fruit, produce"); akin to Old Irish írne "sloe, kernel," Welsh eirin "plums, sloes," aeron "fruits, berries," going back to Celtic *agrinyo-, *agranyo-; perhaps further akin to a Balto-Slavic word with an initial long vowel (Old Church Slavic agoda "fruit," Polish jagoda "berry," Lithuanian úoga)

Note: Taken to be a derivative of Indo-European *h₂eǵros "uncultivated field, pasture" (see acre), though this would seem to exclude the Balto-Slavic etymon, which lacks the suffix, from consideration. It is also not clear if fields, uncultivated or not, are the source of wild tree nuts.

First Known Use

before the 12th century, in the meaning defined above

Phrases Containing acorn

• acorn squash
• acorn woodpecker
• acorn worm

Kids Definition

acorn

noun

ˈā-ˌkȯrn  -kərn 

: the roundish one-seeded thin-shelled nut of an oak tree usually having a woody cap