Definition of adder in English:



  • 1A small venomous Eurasian snake that has a dark zigzag pattern on its back and bears live young.

    Also called viper
    • ‘Along with the loss of heather and cottongrass, birds such as the nightjar, woodlark and stone curlew and animals including the adder, grass snake, and viviparous lizard have been put at risk.’
    • ‘Frogs, toads, lizards and foot-long slow worms are common in the area, as well as poisonous adders.’
    • ‘The mating system and spacing pattern of adders largely agree with those of sand lizards.’
    • ‘There are also reptiles, like adders or grass snakes, slow-worms and lizards that are prone to fire damage because they cannot get out quickly enough.’
    • ‘The most interesting part was when the lecturer talked about a character called William Bunting, who used to catch wild adders to feed to the mongooses at London Zoo.’
    1. 1.1 Used in names of snakes that are similar or related to the adder, e.g., death adder, puff adder.
      • ‘A side-winding adder buries itself just beneath the hot sand exposing only its eyes, patiently waiting for unsuspecting prey.’
      • ‘The ‘horns’ of his horned adder, resembling a stunning set of false eyelashes, would have drag queens running for cover.’


Old English nædre serpent, adder of Germanic origin; related to Dutch adder and German Natter. The initial n was lost in Middle English by wrong division of a naddre; compare with apron, auger, and umpire.