[adj] based on or belonging to etymology; "I merely drew an etymological distinction"
ETYMOLOGICAL is a 12 letter word that starts with E.
Webster's 1913 Dictionary
Definition:
\Et`y*mo*log"ic*al\ (-m[-o]*l[o^]j"[i^]*kal), a.
[L. etymologicus, Gr. 'etymologiko`s: cf. F. ['e]tymologique.
See {Etymology}.]
Pertaining to etymology, or the derivation of words. --
{Et`y*mo*log"ic*al*ly}, adv.
WordNet Dictionary