c.1300, from L.
basiliscus, from Gk.
basiliskos "little king," dim. of
basileus "king;" said to have been so called because of a crest or spot on its head resembling a crown.
"The basilisk has since the fourteenth century been confused with the Cockatrice, and the subject is now a complicated one." [T.H.White]
Its breath and glance were said to be fatal. The South American lizard so called (1813) because it, like the mythical beast, has a crest. Also used of a large cannon, throwing shot of 200 lb., in 1549.