"building for worship, edifice dedicated to the service of a deity or deities," Old English tempel, from Latin templum "piece of ground consecrated for the taking of auspices, building for worship of a god," of uncertain signification.
Commonly referred to PIE root *tem- "to cut," on notion of "place reserved or cut out" [Watkins], or to root *temp- "to stretch" [Klein, de Vaan], on notion of "cleared (measured) space in front of an altar" (from PIE root *ten- "to stretch;" compare temple (n.2)), the notion being perhaps the "stretched" string that marks off the ground. Compare Greek temenos "sacred area around a temple," literally "place cut off," from stem of temnein "to cut." Figurative sense of "any place regarded as occupied by divine presence" was in Old English. Applied to Jewish synagogues from 1590s.