The term was invented by the Swiss alchemist Paracelsus in the 16th century to describe a spirit of the air, one of the elemental beings in his occult philosophy. He likely created it by blending the Latin sylvestris, meaning "of the woods," with nympha, a "nymph," to evoke a creature of the forest air. The word entered broader literary English in the 18th century, notably used by Alexander Pope. Over time, its meaning shifted from a purely mythical air spirit to its modern figurative sense describing a woman of slender and delicate grace, capturing an ethereal, air-like quality.

The word is a simplex loanword. It was coined in its modern form by Paracelsus in the 16th century, likely based on the Latin sylvestris (of the woods) and nympha (nymph), but its precise morphological breakdown in English is not transparent.