From Swedish pyske  "small fairy."

In English folklore, Puck is a mythological fairy or mischievous nature sprite. Puck is also a generalised personification of land spirits. In more recent times, the figure of Robin Goodfellow is identified as a puck.

Puck is also used in many books such as the Sisters Grimm made by Micheal Buckly. The Old English "puca" is a kind of half-tamed woodland sprite, leading folk astray with echoes and lights in nighttime woodlands (like the German and Dutch "Weisse Frauen" and "Witte Wieven" and the French "Dames Blanches," all "White Ladies"), or coming into the farmstead and souring milk in the churn.

According to the Oxford English Dictionary, the etymology of the name Puck is "unsettled", and it is not clear even whether its origin is Germanic (cf. Old Norse puki, Old Swedish puke, Icelandic puki, Frisian Puk), or Celtic (Welsh pwca Cornish Bucca and Irish púca).

One inference would surmise that a theoretical Proto-Indo-European original for both is earlier than the linguistic split.