A gnome (/noʊm/) is a mythological creature and diminutive spirit in Renaissance magic and alchemy, introduced by Paracelsus in the 16th century and widely adopted by authors, including those of modern fantasy literature. They are typically depicted as small humanoids who live underground. Gnome characteristics are reinterpreted to suit various storytellers and artists.

Paracelsus's gnome is recognized to have derived from the German miners' legend about Bergmännlein or dæmon metallicus, the "metallurgical or mineralogical demon", according to Georg Agricola (1530), also called virunculus montanos (literal Latinization of Bergmännlein = "mountain manikin") by Agricola in a later work (1549), and described by other names such as cobeli (sing. cobelus; Latinization of German Kobel). Agricola recorded that according to the legends of that profession, these mining spirits acted as miming and laughing pranksters who sometimes threw pebbles at miners, but could also reward them by depositing a rich vein of silver ore.

Paracelsus also called his gnomes occasionally by these names (Bergmännlein, etc.) in the German publications of his work (1567). Paracelsus claimed gnomes measured 2 spans (18 inches) in height, whereas Agricola had them to be 3 dodrans (3 spans, 27 inches) tall.

The name of the element cobalt descends from kobelt, a 16th century German miners' term for unwanted ore (cobalt-zinc ore, or possibly the noxious cobaltite and smaltite), related as mischief perpetrated by the gnome Kobel (cf. § cobalt ore). This Kobel is a synonym of Bergmännlein, technically not the same as kobold, but there is confusion or conflation between them.

The terms Bergmännlein/Bergmännchen or Berggeist [de] are often used in German publications as the generic, overall term for the mine spirits told in "miners' legends" (Bergmannssage).

Lawn ornaments crafted as gnomes were introduced during the 19th century, growing in popularity during the 20th century as garden gnomes.

The word comes from Renaissance Latin gnomus, gnomos, (pl. gnomi) which first appears in A Book on Nymphs, Sylphs, Pygmies, and Salamanders, and on the Other Spirits by Paracelsus, published posthumously in Nysa in 1566.

The term may be an original invention of Paracelsus, possibly deriving the term from Latin *gēnomos, itself representing a Greek *γηνόμος, approximated by "*gē-nomos", literally "earth-dweller". This is characterized by the Oxford English Dictionary (OED) as a case of "blunder", presumably referring to the omission of the ē to arrive at gnomus. However, this conjectural derivation is not substantiated by any known prior attestation in literature, and one commentator suggests the truth will never be known, short of a discovery of correspondence from the author.