Is karn.aka, 'centre', 'rim' (Skt.) cognate with Greek
koro_nos, 'curved'?
Skt. karn.aka = handle of a vessel; a ring; m.du. the two legs spread
out; ear-ring; central point, centre. In Santali, kanka = rim of a
pot.
ENTRY: circle
Middle English cercle, from Old French, from Latin circulus,
diminutive of circus, circle, from Greek kirkos, krikos.
ENTRY: sker-2
ranch, range, rank1, rink; arrange, derange, from Old French renc,
reng, line, row; c. ringhals, from Middle Dutch rinc (combining form
ring-), a ring. ac all from Germanic *hringaz, something curved,
circle...10. Suffixed o-grade form *kor-o_no-. corona, crown, koruna,
krona1, krona, krone1, krone, from Greek koro_nos, curved. Source:
http://www.bartleby.com/61/roots/IE468.html