1. (v. i.) Any one of numerous species of invertebrate animals which more or less resemble plants in appearance, or mode of growth, as the corals, gorgonians, sea anemones, hydroids, bryozoans, sponges, etc., especially any of those that form compound colonies having a branched or treelike form, as many corals and hydroids.

2. (v. i.) Any one of the Zoophyta.