Also, Kerberos. Classical Mythology . a dog, usually represented as having three heads, that guarded the entrance of the infernal regions.

a formidable and often surly keeper or guard.

(Greek mythology) the three-headed dog guarding the entrance to Hades; son of Typhon

(Class. Myth.) A monster, in the shape of a three-headed dog, guarding the entrance into the infernal regions, Hence

Any vigilant custodian or guardian, esp. if surly.

(Zo["o]l.) A genus of East Indian serpents, allied to the pythons; the bokadam.