According to some scholars, Common Germanic *hunDa- 'dog' (st. m.) is connected with Greek <kúo:n>, Sanskrit <s'vá:>, etc., but the required derivational morphology is bizarre. To the weak stem *k^un- (acc. pl. Grk. <kúnas>, Skt. <s'únah.>) is appended the oxytone suffix *-tó, usually found in passive participles, yielding *k^untó-. Replacing the weak stem with a "zero-grade" *k^wn.-, as though the Greek and other 'dog' words were somehow derived from a "normal" root *k^wen-, does not change the Germanic result. One could equally well attach a paroxytone *-dHo- yielding *k^úndHo-, since the function of the suffix on a root already meaning 'dog' is not explained.
Another possibility is connection with the Gmc. verb *henþ- (st. III) found in Gothic <frahinþan>, <-hanþ>, <-hunþans> 'to capture, imprison', Swedish <hinna> 'to obtain, reach', Danish dialectal <hinne> 'id.', for which the original sense of the simplex is thought to be 'capture'. Here however we should consider the force of Goth. <fra->. With verbs of motion, the corresponding Skt. <pra-> can indicate the motion going to completion: <pad-> 'fall', <prapad-> 'fall to'; <ks.ip-> 'throw', <praks.ip-> 'throw into'; <i-> 'go', <pre-> 'go to the end, die'. This allows us to see *henþ- as the regular Gmc. reflex of PIE *k^ent- 'prick, goad, incite', whence Greek <kentéo:> 'I prick, goad, sting' (earlier *kénto:, Epic 1st aor. inf. <kénsai>), <kéntron> 'point, sting, goad, spur', <kontós> 'pike-shaft, pole'; Latvian <si:ts> 'hunting spear'; Old High German <hantag> 'pointed'; etc. The sense of *henþ- in this view is 'incite, urge into motion, chase', and of Goth. <frahinþan> 'to chase to the end', i.e. 'to catch'.
Now if Gmc. *hunDa- is derived from PIE *k^ent-, it cannot represent a participial *k^n.ttó-, but must continue a simple zero-grade oxytone *k^n.tó- parallel to *yugó- 'yoke' (Skt. <yugám>, Grk. <zugón>, Latin <jugum>, Gmc. *yuka-, etc.) from *yeug- 'join'. The yoke is what facilitates joining oxen, and the hound is what facilitates chasing game, flushing it out of the brush toward a spot where it can be caught or killed.
DGK