thallus

[thal-uh s]

noun, plural thal·li [thal-ahy] /ˈθæl aɪ/, thal·lus·es. Botany, Mycology.

a simple vegetative body undifferentiated into true leaves, stem, and root, ranging from an aggregation of filaments to a complex plantlike form.

Origin of thallus

1820–30; < New Latin < Greek thallós young shoot, twig

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for thallus

Historical Examples of thallus

The colouring matter is ready formed and abundant in the thallus.
Vegetable Dyes
Ethel M. Mairet
The thallus does not yet show this important morphological division.
The Wonders of Life
Ernst Haeckel
The structure of the thallus may serve to represent that of most of the Lichens.
An Elementary Text-book of the Microscope
John William Griffith
Antheridia immersed in the thallus, covered with dentate scales.
The Manual of the Botany of the Northern United States
Asa Gray
Piece of thallus of Parmelia conspersa, with section through an apothecium.
The Elements of Botany
Asa Gray

British Dictionary definitions for thallus

thallus

noun plural thalli (ˈθælaɪ) or thalluses

the undifferentiated vegetative body of algae, fungi, and lichens

Derived Formsthalloid, adjective

Word Origin for thallus

C19: from Latin, from Greek thallos green shoot, from thallein to bloom

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for thallus

Latin, from Greek thallos "green shoot, twig," related to thalia "abundance," thalos "scion, child," ultimately from PIE root *dhal- "to bloom" (cf. Old Irish duilesc, a type of algae).

Medicine definitions for thallus

thallus

[thăl′əs]

n. pl. thal•lus•es

A plant body or fungus undifferentiated into stem, root, or leaf.

Science definitions for thallus

thallus

[thăl′əs]

Plural thalli (thăl′ī)

A type of body found among plants and fungi that is not differentiated into roots, stems, or leaves. Thalli are found among lichens, mosses, liverworts, and many algae, as well as the gametophyte generations of horsetails and ferns, which have rhizoids but not true roots.