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

But the fields that sloped toward the turquoise sea weren’t about to be cultivated with the vines of Merlot grapes or Regona cider apple trees or even acorns to be transmuted into jamón Ibérico. —Tamar Adler, Vogue, 3 June 2026

The exhibit of work by Saya Woolfalk will will combine science fiction and storytelling with large plants, acorn spaceships, interactive environments and more. —Abby Hamblin, San Diego Union-Tribune, 3 June 2026

Theirs is a black iron double gate adorned with gold acorns. —ABC News, 26 May 2026

Scientists speculated that the uptick in attacks has been driven by a growing bear population, coupled with the year's bad acorn harvest, USA TODAY previously reported. —Mary Walrath-Holdridge, USA Today, 13 May 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