'Basilisk' definitions:

Definition of 'basilisk'

noun

(classical mythology) a serpent (or lizard or dragon) able to kill with its breath or glance

noun

Ancient brass cannon

noun

Small crested arboreal lizard able to run on its hind legs; of tropical America

From: GCIDE

Basilisk \Bas"i*lisk\, n. [L. basiliscus, Gr. basili`skos little king, kind of serpent, dim. of basiley`s king; -- so named from some prominences on the head resembling a crown.]
1. 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. [1913 Webster]
Make me not sighted like the basilisk. --Shak. [1913 Webster]
2. (Zool.) A lizard of the genus Basiliscus, belonging to the family Iguanid[ae]. [1913 Webster]
Note: This genus is remarkable for a membranous bag rising above the occiput, which can be filled with air at pleasure; also for an elevated crest along the back, that can be raised or depressed at will. [1913 Webster]
3. (Mil.) A large piece of ordnance, so called from its supposed resemblance to the serpent of that name, or from its size. [Obs.] [1913 Webster]

Basilisk (in R.V., Isa. 11:8; 14:29; 59:5; Jer. 8:17), the "king serpent," as the name imports; a fabulous serpent said to be three spans long, with a spot on its head like a crown. Probably the yellow snake is intended. (See COCKATRICE.)