indusium

noun

in·​du·​si·​um in-ˈdü-zē-əm 

-ˈdyü-,

-zhē- 

plural indusia in-ˈdü-zē-ə 

-ˈdyü-,

-zhē- 

: an investing outgrowth or membrane

especially : an outgrowth of a fern frond that covers the sori

Word History

Etymology

New Latin, from Latin, tunic

First Known Use

1807, in the meaning defined above

Medical Definition

indusium

noun

in·​du·​si·​um in-ˈd(y)ü-z(h)ē-əm 

plural indusia -z(h)ē-ə 

: a membrane serving as a covering

especially : indusium griseum