thallus
noun
thal·lus ˈtha-ləs 
plural thalli ˈtha-ˌlī
-ˌlē
or thalluses : a plantlike vegetative body (as of algae, fungi, or mosses) that lacks differentiation into distinct parts (such as stem, leaves, and roots) and does not grow from an apical point
Word History
Etymology
New Latin, from Greek thallos, from thallein to sprout; akin to Armenian dalar green, fresh, Albanian dal I come forth
First Known Use
1829, in the meaning defined above
Medical Definition
thallus
noun
thal·lus ˈthal-əs
plural thalli ˈthal-ˌī -ˌē or thalluses
-ˌē or thalluses : a plant or plantlike body (as of an alga, fungus, or moss) that lacks differentiation into distinct members (as stem, leaves, and roots) and does not grow from an apical point