The story
- Old English · inherited fromwæternædre
- Middle English · inherited fromwater addre
- English todaywater adder
From Middle English water addre, watyradyr, watir edyr, alteration (see adder) of water neddyr, watyrnedyre, from Old English wæternædre, wæternǣdre, equivalent to water + adder. Cognate with Dutch wateradder (“wateradder”), German Wassernatter (“watersnake”).
Etymology from Wiktionary, CC BY-SA 4.0.