Acorn

The acorn is the nut of the oaks and their close relatives . It usually contains a seedling surrounded by two cotyledons (seedling leaves), enclosed in a tough shell known as the pericarp, and borne in a cup-shaped cupule. Acorns are 1–6 cm (1⁄2–2+1⁄2 in) long and 0.8–4 cm (3⁄8–1+5⁄8 in) on the fat side. Acorns take between 5 and 24 months (depending on the species) to mature; see the list of Quercus species for details of oak classification, in which acorn morphology and phenology are important factors. 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 c. 15th–16th century) derives from association with ac (Old English: "oak") + corn.