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

Healthy acorns will fall free from the caps. —Karl Schneider, IndyStar, 11 Nov. 2025

The Ministry of Environment blamed this year’s surge on a poor acorn harvest – which drove a similar spate of attacks in 2023. —Jessie Yeung, CNN Money, 7 Nov. 2025

In 1968, Ono and Lennon planted two acorns as a living sculpture for the Exhibition of British Sculpture at Coventry Cathedral in England. —Robert Lang, Deadline, 6 Nov. 2025

The milieu here is rarified and sophisticated, all gallery openings and gourmet restaurants that serve organic pork from pigs who only eat a specific type of acorns. —Katie Rife, IndieWire, 5 Nov. 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