Subkingdom \Sub*king"dom\, n. One of the several primary divisions of either the animal, or vegetable kingdom, as, in zo["o]logy, the Vertebrata, Tunicata, Mollusca, Articulata, Molluscoidea, Echinodermata, C[oe]lentera, and the Protozoa; in botany, the Phanerogamia, and the Cryptogamia.

Source: Webster's Revised Unabridged Dictionary (1913)