lithiasis
Concise Oxford English Dictionary © 2008 Oxford University Press:
lithiasis /lɪˈθʌɪəsɪs/
▶noun Medicine the formation of stones in an internal organ such as the kidney or gall bladder.
– origin C17: from med. L., based on Gk lithos ‘stone’.
'lithiasis' also found in these Oxford entries:

