Hyʹdra

A monster of the Lerʹnean marshes, in Arʹgolis. It had nine heads, and Hercules was sent to kill it. As soon as he struck off one of its heads, two shot up in its place.

Hydra-headed. Having as many heads as the hydra (q.v.); a difficulty which goes on increasing as it is combated.

Hydra-headed multitude. The rabble, which not only is many-headed numerically, but seems to grow more numerous the more it is attacked and resisted.