In Greek mythology, the dríades (Greek: Δρυάδες, Dryádes, from δρῦς, drýs, "oak") were nymphs associated with oak trees. Nymphs of other trees are called hamadríades.
According to an ancient legend, each dríade was born along with a particular tree, from which it exhaled. The Druid lived in or near the tree. When its tree was cut down or killed, the deity would also die. The gods often punished those who destroyed such a tree.
The word druid is also used in a general sense for nymphs who lived in the forest, although alseids are also nymphs associated with woods and forests.
In Roman mythology, there were nymphs of the oak woods, called querquetulanas (querquetulanae) or querquetulanae virae (women of the oak woods), and are therefore similar to the Greek dyads, although their remote origins suggest that this is an originally Roman myth, rather than a Greek incorporation.
Such nymphs were responsible for producing the growth of the foliage of these trees. Their name derives from the Latin term for oak grove, querquetum, which in turn derives from the word quercum, oak.
According to Festus, it was believed that in Rome there had once been an oak grove within the city, at the entrance to the Porta Querquetulana, situated on the Servian Wall; it was the sacred grove of the querquetulanas, whose annual bowing was effected by them.