Hamadryad

The term and concept come from ancient Greek mythic taxonomy of nymphs; the name (ἁμαδρυάς, hamadryás) combines háma ('together, concurrently') and dryás ('tree, wood nymph') and encodes the idea that the nymph's life is concurrent with a particular tree. Classical fragments and summaries treat hamadryads as either spirits born bonded to a single tree on which their life depends or, in some formulations, as the tree's animating presence itself. Myths preserve episodes in which harm to a hamadryad's tree brings divine or nymphal retribution, and remedial sacrifices to the nymph are recorded in narrative sources.

Classical sources identify hamadryads as tree-nymphs (female nature-spirits) tied to particular trees; trees associated with them are described as flourishing, tall, and beautiful. The surviving material does not supply standardized, detailed physical descriptions beyond their personhood as nymphs and their intimate association with a single living tree. Later modern summaries and roleplaying material stylize them further, but such portrayals are secondary to classical attestations.

Hamadryads' defining attribute is that their life is inextricably tethered to a specific living tree: if the tree dies, the hamadryad dies. Within mythic narratives they exercise reciprocal, moral agency toward humans who encounter their tree — rewarding those who protect or save the tree and punishing those who harm it. Classical stories record punishments (for example, the punishment of King Erysichthon and episodes cited in fragments and Apollonius of Rhodes) and also record that propitiatory sacrifices could be required to lift curses incurred by damaging a nymph's tree.