thallus

noun
thal·​lus | \ ˈtha-ləs How to pronounce thallus (audio) \
plural thalli\ ˈtha-​ˌlī How to pronounce thallus (audio) , -​ˌlē \ or thalluses

Definition of thallus

: 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

First Known Use of thallus

1829, in the meaning defined above

History and Etymology for thallus

New Latin, from Greek thallos, from thallein to sprout; akin to Armenian dalar green, fresh, Albanian dal I come forth

Learn More About thallus

Time Traveler for thallus

Time Traveler

The first known use of thallus was in 1829

See more words from the same year

Dictionary Entries Near thallus

thallous

thallus

thalposis

See More Nearby Entries 

Statistics for thallus

Cite this Entry

“Thallus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/thallus. Accessed 10 Aug. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

More Definitions for thallus

thallus

noun
thal·​lus | \ ˈthal-əs How to pronounce thallus (audio) \
plural thalli\ ˈthal-​ˌī How to pronounce thallus (audio) , -​ˌē How to pronounce thallus (audio) \ or thalluses

Medical Definition of thallus

: 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

More from Merriam-Webster on thallus

Britannica.com: Encyclopedia article about thallus

WORD OF THE DAY

Test Your Vocabulary

The Great British Vocabulary Quiz

  • union jack speech bubble
  • Named after Sir Robert Peel, what are British police called?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

TAKE THE QUIZ
Universal Daily Crossword

A daily challenge for crossword fanatics.

TAKE THE QUIZ
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!