ellagic acid
Concise Oxford English Dictionary © 2008 Oxford University Press:
ellagic acid /ɛˈladʒɪk/
▶noun Chemistry a compound extracted from oak galls and some fruits and nuts, able to retard the growth of cancer cells to some extent.
– origin C19: from Fr. ellagique (an anagram of galle ‘gall nut’ + -ique), thus avoiding the form gallique, already in use.
'ellagic acid' also found in these Oxford entries:

