Both Uses

serpent
in
Utopia, by Thomas More
(Auto-generated)

Under the equator, and as far on both sides of it as the sun moves, there lay vast deserts that were parched with the perpetual heat of the sun; the soil was withered, all things looked dismally, and all places were either quite uninhabited, or abounded with wild beasts and serpents, and some few men, that were neither less wild nor less cruel than the beasts themselves.†
*

serpents = snakes
This is that infernal serpent that creeps into the breasts of mortals, and possesses them too much to be easily drawn out;†

serpent = snake

Definitions:

(1) (serpent)
a snake
(2) (meaning too rare to warrant focus)
For less common senses of "serpent", see a comprehensive dictionary.