Hark and Hearken
Hark and hearken (also harken) both mean to listen with attention, heed
hearken is from Old English hercnian and from the I-E root *keu which is also the source of hear and of Greek
akou/ein > acousticThe idiom hark back means "to return to a previous point"
This is often heard as "hearken back" which has become so common that it may now be correct.
Return to WORDS