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

Today, ubiquitous green acorn signs for Kettle Moraine Scenic Drive make navigation a snap. — Hannah Agran, Midwest Living, 12 Sep. 2026

Choose from colorful leaves, pumpkins, or acorns for a 12-count pack. — Rebecca Jones, Southern Living, 9 Sep. 2026

Tourists coming to the Bay Area are more likely to beeline it to the Pacific beaches or charming environs of Wine Country, not to a town whose mascot is an anthropomorphic acorn and whose name honors a settler’s mother-in-law. — John Metcalfe, Mercury News, 3 Sep. 2026

In the upper South and other regions, white oak acorns are preferred—chestnut white oak acorns, in particular. — Colin Moore, Outdoor Life, 2 Sep. 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