lexicon

Through Middle French or directly from New Latin lexicon, from Medieval Greek λεξικόν (lexikón, “a lexicon, a dictionary”), ellipsis from Ancient Greek λεξικὸν βιβλίον (lexikòn biblíon, literally “a book of words”), from λεξικός (lexikós, “of words”), from λέξις (léxis, “a saying, speech, word”), from λέγω (légō, “to speak”), ultimately from Proto-Indo-European *leǵ- (“to gather, collect”).

Attested at least since 1583 (in William Fulke's A Defense of the Sincere and True Translations of the Holy Scriptures into the English tongue) in the sense 'a dictionary of a classical language'.