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

Oaks are famous for their acorns, which aren’t just consumed by animals but also by birds such as woodpeckers and jays. —Luke Miller, Better Homes & Gardens, 11 July 2025

There were oak ridges thick with acorns, an abundance of berries and wild cherries, stumps and logs to supply ants, and even hornet nests to knock down. —Carl T. Johnson, Outdoor Life, 2 July 2025

Experts attributed that to oak trees producing a larger-than-expected number of acorns, which allowed larger numbers of deer and other animals that ticks prey on to survive. —Meg Wingerter, Denver Post, 4 July 2025

Moths chew holes in cabbage; squirrels plant acorns in the garlic plot. —Ryan Murphy, IndyStar, 2 July 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