The acorn, or oaknut, is the nut of the oaks and their close relatives .
The word acorn (earlier akerne, and acharn) is related to the Gothic name akran, which had the sense of "fruit of the unenclosed land".
The word was applied to the most important forest produce, that of the oak. Chaucer spoke of "achornes of okes" in the 14th century. By degrees, popular etymology connected the word both with "corn" and "oak-horn", and the spelling changed accordingly.
The current spelling (emerged 15c.-16c.), derives from association with ac (Old English: "oak") + corn.