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

The monster is content surviving on acorns and berries. —Big Think, 22 Apr. 2026

Red foxes tend to eat more meat, while gray foxes eat meat but also more plant materials such as acorns or beechnuts, says Owen. —Arricca Elin Sansone, Southern Living, 16 Apr. 2026

Bears will often ignore seasonally available natural foods, like acorns and nuts, in favor of an easy meal at a backyard bird feeder. —Rick Sobey, Boston Herald, 9 Apr. 2026

These include delicata, acorn, and spaghetti squash, which can all be planted outdoors in April once the threat of frost has passed, Tegen says. —Cori Sears, The Spruce, 7 Apr. 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