Dryad

A dryad is a tree nymph from Greek mythology, traditionally associated with oak trees. The word comes from the Greek "drys" (δρῦς) meaning "oak." While originally specific to oak trees, the term is now commonly used for tree nymphs of any kind.

These nature spirits were believed to live extraordinarily long lives and were deeply connected to their woodland homes. A special type of dryad called a hamadryad shared such a profound bond with its tree that the spirit's life force was completely intertwined with it - if the tree died, so did the hamadryad. Because of this sacred connection, mortals who damaged trees without first seeking the dryads' blessing risked severe punishment from both the nymphs and the Greek gods.