ae·​ci·​um | \ ˈē-shē-əm How to pronounce aecium (audio) , ˈē-sē-\
plural aecia\ ˈē-​shē-​ə How to pronounce aecia (audio) , ˈē-​sē-​ \

Definition of aecium

: the fruiting body of a rust fungus in which the first binucleate spores are usually produced

Other Words from aecium

aecial \ ˈē-​sh(ē-​)əl How to pronounce aecial (audio) \ adjective

First Known Use of aecium

1905, in the meaning defined above

History and Etymology for aecium

back-formation from aecidium "a cup-shaped or spheroidal aecium," borrowed from New Latin, irregularly for *oecidium, borrowed from Greek oikídion, diminutive of oîkos "house, abode, room" — more at vicinity, -idium

Note: Word introduced as a substitute for aecidium by the Purdue University plant pathologist J. C. Arthur (1850-1942) in an effort to reform terminology for rust fungi; see "Terminology of the Spore-Structures in the Uredinales," Botanical Gazette, vol. 39 (Mar., 1905), pp. 219-22. Arthur in the same article introduced aecial and aeciospore. The earlier word aecidium was coined as a genus name by the author and botanist John Hill, in A General Natural History, or New and Accurate Descriptions of the Animals, Vegetables, and Minerals, of the Different Parts of the World, vol. II, A History of Plants (London: Printed for Thomas Osborne, 1751). Hill states on p. 64: "We have called this genus, distinguished by its peculiar cells, Æcidium, from the Greek οικιδιον, cellula." Since the 19th century dictionaries and mycological references have assumed on no grounds other than appearance that the word was borrowed from Greek aikía, "maltreatment, outrage, torture." (See, for example, Miguel Ulloa and Richard T. Hanlin, Illustrated Dictionary of Mycology [St. Paul: American Phytopathological Society, 2000], where aikía is incorrectly glossed "wound, lesion.") Hill might have avoided misinterpretation by transliterating the word oecidium, but given the identity of <ae> and <oe> in English pronunciation, the distinction may have seemed trifling.

Keep scrolling for more

Learn More about aecium

Dictionary Entries near aecium








Statistics for aecium

Last Updated

17 Sep 2019

Look-up Popularity

Time Traveler for aecium

The first known use of aecium was in 1905

See more words from the same year

More from Merriam-Webster on aecium Encyclopedia article about aecium

Comments on aecium

What made you want to look up aecium? Please tell us where you read or heard it (including the quote, if possible).


transposition of initial sounds of words

Get Word of the Day daily email!

Test Your Vocabulary

Word Puzzles

  • alt 57589b2b4c6a3
  • Which answer pairs best with each of the following words? living, estate, club, music, road, mile
Spell It

Can you spell these 10 commonly misspelled words?

Syn City

Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

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