2. (Zo["o]l.) One of the transverse plants found in the
calicles of certain corals and hydroids.
{Tabula rasa}[L.], a smoothed tablet; hence, figuratively,
the mind in its earliest state, before receiving
impressions from without; -- a term used by Hobbes, Locke,
and others, in maintaining a theory opposed to the
doctrine of innate ideas.