The mediaeval name (a corruption of “crocodile”) of a fabulous serpent supposed to be produced from a cock’s egg. It is generally supposed to denote the cerastes, or “horned viper,” a very poisonous serpent about a foot long. Others think it to be the yellow viper (Daboia xanthina), one of the most dangerous vipers, from its size and its nocturnal habits (Isa. 11:8; 14:29; 59:5; Jer. 8:17; in all which the Revised Version renders the Hebrew tziph’oni by “basilisk”). In Prov. 23:32 the Hebrew tzeph’a is rendered both in the Authorized Version and the Revised Version by “adder;” margin of Revised Version “basilisk,” and of Authorized Version “cockatrice.”
Cockatrice
Isaiah once pictures a world where “the sucking child shall play on the hole of the asp, and the weaned child shall put his hand on the cockatrice’ den.” The cockatrice is a deadly snake, a creature to be feared, which is exactly why that picture of safety is so striking. The other verses use it as a warning. Jeremiah hears the Lord say, “I will send serpents, cockatrices, among you, which will not be charmed,” and Isaiah says of the wicked, “They hatch cockatrice’ eggs.” The word names a venomous snake, nothing more specific. Isaiah 11:6-9 is the gentler passage to read first.
4 verses
Isaiah
And the sucking child shall play on the hole of the asp, and the weaned child shall put his hand on the cockatrice' den.
Rejoice not thou, whole Palestina, because the rod of him that smote thee is broken: for out of the serpent's root shall come forth a cockatrice, and his fruit shall be a fiery flying serpent.
They hatch cockatrice' eggs, and weave the spider's web: he that eateth of their eggs dieth, and that which is crushed breaketh out into a viper.
Jeremiah
For, behold, I will send serpents, cockatrices, among you, which will not be charmed, and they shall bite you, saith the LORD.
From Easton's Bible Dictionary
Matthew George Easton, 1897