What's the difference between cockatrice and wyvern?

Cockatrice

Definition:

• (n.) A fabulous serpent whose breath and look were said to be fatal. See Basilisk.
• (n.) A representation of this serpent. It has the head, wings, and legs of a bird, and tail of a serpent.
• (n.) A venomous serpent which which cannot now be identified.
• (n.) Any venomous or deadly thing.

Example Sentences:

Wyvern

Definition:

• (n.) Same as Wiver.

Example Sentences:

• (1) Bauer is now understood to be the preferred bidder for Heart 106 in the east Midlands, and BRMB, Beacon, Mercia and Wyvern in the West Midlands.