'drake' originates from Old English 'draca', ultimately from Latin 'draco' and Greek 'drakon', where 'drakon' meant 'serpent' or 'dragon'.

'draca' in Old English developed into Middle English 'drake' (used for 'dragon'); the sense 'male duck' also became established in English, and both senses existed though the 'dragon' sense became more literary/archaic.

Initially associated with 'dragon' or 'serpent', the word later came to be applied to the male of the duck (and retained an archaic literary sense of 'dragon').