rhi·zoid / ˈrīˌzoid/ • n. Bot. a filamentous outgrowth or root hair on the underside of the thallus in some lower plants, esp. mosses and liverworts, serving both to anchor the plant and (in terrestrial forms) to conduct water.DERIVATIVES: rhi·zoi·dal / rīˈzoidl/ adj.

rhizoid In mosses and liverworts: a thread-like structure, often serving to anchor the plant (gametophyte) to the substrate; rhizoids can absorb water and minerals. In mosses rhizoids are multi-cellular, in liverworts they are unicellular.

rhizoid Fine, hairlike growth used for attachment to a solid surface by some simple organisms, such as certain fungi and mosses. The rhizoid lacks the conducting tissues of a root.

rhizoid One of a group of delicate and often colourless hairlike outgrowths found in certain algae and the gametophyte generation of bryophytes and ferns. They anchor the plant to the substrate and absorb water and mineral salts.