Wikipedia
Hörgr
A hörgr ( Old Norse, plural hörgar) or hearg ( Old English) was a type altar or cult site, possibly consisting of a heap of stones, used in Norse religion, as opposed to a roofed hall used as a hof (temple).
The Old Norse term is attested in both the Poetic Edda and the Prose Edda, in the sagas of Icelanders, skaldic poetry, its Old English cognate in Beowulf. The word is also reflected in various place names (in English placenames as harrow), often in connection with Germanic deities.
Old Norse hǫrgr "altar, sanctuary", Old English hearg " holy grove; temple, idol". Old High German harug continue a Proto-Germanic *harugaz, possibly cognate with Insular Celtic carrac "cliff".