The Greek word probably derives from an Indo-European base * derḱ- meaning 'to see' the Sanskrit root दृश् ( dr̥ś-) also means 'to see'. This is thought to have referred to something with a 'deadly glance,' or unusually bright or 'sharp' eyes, or because a snake's eyes appear to be always open each eye actually sees through a big transparent scale in its eyelids, which are permanently shut. The Greek word δράκων is most likely derived from the Greek verb δέρκομαι ( dérkomai) meaning 'I see', the aorist form of which is ἔδρακον ( édrakon). The Greek and Latin term referred to any great serpent, not necessarily mythological.
The word dragon entered the English language in the early 13th century from Old French dragon, which, in turn, comes from the Latin: draco (genitive draconis) meaning 'huge serpent, dragon', from Ancient Greek δράκων, drákōn (genitive δράκοντος, drákontos) 'serpent'.
Etymology An early appearance of the Old English word dracan in Beowulf
