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

Participants will water, weed and mulch oak trees, and plant acorns to replace trees that have died. — Jaclyn Cosgrove, Los Angeles Times, 30 July 2026

Between October and February, black Iberian pigs feast on the acorns beneath the trees; in the spring, sheep are shipped in to graze. — Lucy Gillmore, Travel + Leisure, 30 July 2026

This was a funhouse reality, in which children were lost and predators roamed, but through which white harts leapt through shafts of sunlight, songbirds trilled, and where honey and berries and acorns might be foraged for free. — Literary Hub, 30 July 2026

One of the best oaks for wildlife, including birds, is the Chinkapin oak (Quercus muehlenbergii), which annually matures a crop of small, sweet acorns easily accessed and transported by birds. — Luke Miller, Better Homes & Gardens, 18 July 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