acorn

Từ điển Oxford Advanced Learner 8th

acorn [acorn acorns] BrE [ˈeɪkɔːn] NAmE [ˈeɪkɔːrn] noun
the small brown nut of the ↑oak tree, that grows in a base shaped like a cup
see great/tall oaks from little acorns grow at ↑oak

Word Origin:
Old English æcern, of Germanic origin; related to Dutch aker, also to ↑acre, later associated with ↑oak and the plant ↑corn.