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

This new musical, based on the global preschool sensation, follows Gabby as discovers an acorn that needs a rainbow to grow. —Caroline Ritzie, Cincinnati Enquirer, 1 Feb. 2026

Known as a granary tree, the same tree is often used year after year and may contain upward of 50,000 acorns. —Ernie Cowan, San Diego Union-Tribune, 1 Feb. 2026

Taking inspiration from her family's custom coat of arms, as well as the Cartier Halo tiara (the diadem Middleton paired with her stunning Alexander McQueen gown), the earrings feature acorn and oak leaf motifs. —Hannah Malach, InStyle, 21 Jan. 2026

The event, complete with interactive 3D stations, was set to include a performance by Evolve Altadena, and TreePeople giving out acorns. —Staff Report, Daily News, 12 Jan. 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