cynosure (n.)

Proto-Indo-European root meaning "dog."

It forms all or part of: canaille; canary; canicular; canid; canine; chenille; corgi; cynic; cynical; cynosure; dachshund; hound; kennel; Procyon; quinsy.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit svan-, Avestan spa, Greek kyōn, Latin canis, Old English hund, Old High German hunt, Old Irish cu, Welsh ci, Russian sobaka (apparently from an Iranian source such as Median spaka), Armenian shun, Lithuanian šuo "dog."

"buttocks, hinder part of an animal," Old English ærs "tail, rump," from Proto-Germanic *arsoz (source also of Old Saxon, Old High German, Old Norse ars, Middle Dutch ærs, German Arsch "buttock"), from PIE root *ors- "buttock, backside" (source also of Greek orros "tail, rump, base of the spine," Hittite arrash, Armenian or "buttock," Old Irish err "tail").

To hang the arse "be reluctant or tardy" is from 1630s. Middle English had arse-winning "money obtained by prostitution" (late 14c.). To turn arse over tip is attested by 1884, along with the alternative arse over tit.

Every scrap of Latin Lord Edgecumbe heard at the Encaenia at Oxford he translated ridiculously; one of the themes was Ars Musica : he Englished it Bumfiddle. [Horace Walpole to the Countess of Upper Ossory, Aug. 9, 1773]