From the vocabulary word denoting the evergreen shrub or tree (Middle English holi(n), Old English holegn). The name was first used at the beginning of the 20th century, and has been particularly popular since the 1990s. It is bestowed especially on girls born around Christmas, when sprigs of holly are traditionally taken indoors to decorate rooms.
German: from Middle High German kīl ‘wedge’, ‘wooden peg’, hence possibly a metonymic occupational name for a maker of such pegs or for a wood chopper. Alternatively, it may be nickname for an uncouth or misshapen person (compare Keidel) or a topographic name for someone who lived on or near a wedgeshaped plot of land.