- A slender rootlike filament that grows from an alga, a fungus, or the gametophyte of a moss, liverwort, or fern, used for attachment and nourishment.
- In <em>botany</em> and <em>zoology</em>, root-like; resembling a root.
- In <em>botany</em>, a filamentous organ resembling a root, but of simple structure, found on compound thalli of all kinds, and on the stems of the <em>Muscineæ.</em>
- Rhizoids are numerously produced, and their function is the attachment of the plant to the substratum. The older term was <em>rhizina.</em> See cut under <internalXref urlencoded="prothallium">prothallium</internalXref>.
- A rootlike appendage.
- A <xref>rootlike</xref> <xref>structure</xref> in <xref>fungi</xref> and some <xref>plants</xref> that acts as <xref>support</xref> and/or aids the <xref>absorption</xref> of nutrients.
- any of various slender filaments that function as roots in mosses and ferns and fungi etc