Webster's Revised Unabridged Dictionary · 1913

Echidna

Echidna (e*kid"nȧ) , noun

[Latin, a viper, adder, Greek 'e`chidna.]

1.
(Greek Mythology) A monster, half maid and half serpent.
2.
(Zoology) A genus of Monotremata found in Australia, Tasmania, and New Guinea. They are toothless and covered with spines; -- called also porcupine ant-eater, and Australian ant-eater.