Jowett: aischron

Her. Very likely you are right ; but suppose that we leave these words and endeavour to see the rationale of kalon and aischron. CRATYLUS  

Soc. The meaning of aischron is evident, being only aei ischon roes (always preventing from flowing), and this is in accordance with our former derivations. For the name-giver was a great enemy to stagnation of all sorts, and hence he gave the name aeischoroun to that which hindered the flux (aei ischon roun), and that is now beaten together into aischron. CRATYLUS