Skullcap \Skull"cap`\, n.

1. A cap which fits the head closely; also, formerly, a headpiece of iron sewed inside of a cap for protection.

2. (Bot.) Any plant of the labiate genus Scutellaria, the calyx of whose flower appears, when inverted, like a helmet with the visor raised.

3. (Zo["o]l.) The Lophiomys.

Mad-dog skullcap (Bot.), an American herb (Scetellaria lateriflora) formerly prescribed as a cure for hydrophobia.

Source: Webster's Revised Unabridged Dictionary (1913)