In North-European mythology, a dwarfish imp inhabiting the interior parts of the earth and having special custody of mineral treasures. Bjorsen, who died in 1765, says gnomes were common enough in the southern parts of Sweden in his boyhood, and he frequently saw them scampering on the hills in the evening twilight. Ludwig Binkerhoof saw three as recently as 1792, in the Black Forest, and Sneddeker avers that in 1803 they drove a party of miners out of a Silesian mine. Basing our computations upon data supplied by these statements, we find that the gnomes were probably extinct as early as 1764.
"Muggles have garden gnomes too, you know," Harry told Ron as they crossed the lawn.
"Yeah, I've seen those things they think are gnomes," said Ron, bent double with his head in a peony bush. "Like fat little Father Christmases with fishing rods..."
There was a violent scuffling noise, the peony bush shuddered, and Ron straightened up.
"This is a gnome," he said grimly. [...] It was certainly nothing like Father Christmas. It was small and leathery-looking, with a large, knobbly, bald head exactly like a potato.
Few who deal with gnomes regularly are capable of forgetting it, but one fact bears repeating: gnomes are alien to Golarion. No matter how many thousands of years they’ve spent on the Material Plane, the gnomes are not a natural part of its landscape and did not evolve as part of any given ecological niche. They speak the language of the fey guardians of the natural world, but their roots with the nature beings lie farther back, in the First World that existed long before the Material Plane. Gnomes may be visitors, long-term residents, or naturalized citizens—but never natives.
To the gnome mind, both the smell of an unfamiliar flower and the wet pop of a squeezed eyeball are equally novel sensations.
— Pathfinder Companion: Gnomes of Golarion