immemorial
Concise Oxford English Dictionary © 2008 Oxford University Press:
immemorial/ɪməˈmɔːriəl/
▶adjective very old or long past: from time immemorial.
– derivatives
immemorially adverb.
immemorially adverb.
– origin C17: from med. L. immemorialis, from in- ‘not’ + memorialis ‘relating to the memory’.
'immemorial' also found in these Oxford entries:
