ko·bold 
(kōbôld′)
(kōbôld′)n.
1. An often mischievous household elf in German folklore.
2. A gnome that haunts underground places in German folklore.
[German, from Middle High German kobolt : perhaps Middle High German kobe, pigpen; akin to English COVE1 + Middle High German hold, attached, well-inclined (as a household spirit to a house or farm).]