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

An oak tree sapling planted recently on a hillside next to the bike path was produced from an acorn from another oak tree about 100 yards away on the same path. —Ashley MacKin Solomon, San Diego Union-Tribune, 3 Mar. 2026

With a foreword by fellow Oaklander and Native American author Tommy Orange, Wahpepah’s book invites readers to a pre-colonial cuisine of bison roast with chokeberry rub, acorn muffins and wild rice fritters stuffed with apples, cranberries, pepita crema and much more. —Chase Hunter, Mercury News, 27 Feb. 2026

Organically rich soils are better growing conditions for plants that can do things like produce nectar for pollinators, produce acorns for squirrels, and shade the ground so moisture is better retained. —Campbell Vaughn, USA Today, 21 Feb. 2026

The acorns and berries these tree species produce constitute important food sources for bears. —Shi En Kim, AZCentral.com, 20 Feb. 2026

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