skullcap

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A light, close-fitting, brimless cap sometimes worn indoors.
2. n. A yarmulke.
3. n. Any of various plants of the genus Scutellaria, having clusters of two-lipped flowers.

Century Dictionary and Cyclopedia

1. n. Any cap fitting closely to the head; also, the iron cap of defense. See skull, 4.
2. n. The sinciput; the upper domed part of the skull, roofing over the brain; the calvarium. See cut under cranium.
3. n. A murine rodent quadruped of the family Lophiomyidæ.
4. n. A plant of the genus Scutellaria: so called from the helmet-like appendage to the upper lip of the calyx, which closes the mouth of the calyx after the fall of the corolla. The more familiar species, as S. galericulata, are not showy; others are recommended for the flower-garden, especially S. macrantha from eastern Asia, which produces abundant velvety dark-blue flowers. S. Mociniana is a scarlet-flowered greenhouse species from Mexico. S. lateriflora of North America has had some apparently ill-grounded recognition as a nervine, and was once considered useful in hydrophobia (whence called madweed, or mad-dog skullcap). S. serrata, with large blue flowers, is one of the handsomest wild American species.
5. n. A thin stratum of compact limestone lying at the base of the Purbeck beds, and underlain by a shelly limestone locally known as roach, forming the uppermost division of the Portland series, as this portion of the Jurassic is developed in the so-called Isle of Portland, England.
6. n. In entomology, the upper part of the integument of the head, including the front and vertex.

Wiktionary

1. n. A small domed cap that covers from the forehead to just above the back of the neck.
2. n. A yarmulke-like hat worn as an element of ghetto fashion.
3. n. Any of several species of flowering plants, of the genus Scutellaria, in the Lamiaceae family.

GNU Webster's 1913

1. n. A cap which fits the head closely; also, formerly, a headpiece of iron sewed inside of a cap for protection.
2. n. (Bot.) Any plant of the labiate genus Scutellaria, the calyx of whose flower appears, when inverted, like a helmet with the visor raised.
3. n. (Zoöl.) The Lophiomys.

WordNet 3.0

1. n. the dome of the skull
2. n. a herbaceous plant of the genus Scutellaria which has a calyx that, when inverted, resembles a helmet with its visor raised
3. n. rounded brimless cap fitting the crown of the head