Basilisk n. : A fabulous serpent, or dragon. The ancients alleged that its hissing would drive away all other serpents, and that its breath, and even its look, was fatal. See Cockatrice.

Basilisk n. : A lizard of the genus Basiliscus, belonging to the family Iguanidae.

Basilisk n. : A large piece of ordnance, so called from its supposed resemblance to the serpent of that name, or from its size.

Example:
How did the Basilisk in "Harry Potter and the Chamber of Secrets" get out of the pipes?

Taxonomy
basilisk, eyes of the basilisk, Green Basilisk, plumed basilisk, serpents, gaze, eyes, snake, king, lizard, creature, rooster, David Langford, power, the legend, cockatrice, monster, spear.

Defination from the web:
basilisk ... According to the Naturalis Historia of Pliny the Elder, the basilisk of Cyrene is a small snake, "being not more than twelve fingers in length" ...