noun did·y·mo \ˈdi-də-ˌmō, -dē-\

Definition of didymo

  1. :  a freshwater, microscopic diatom (Didymosphenia geminata) typically of cool, nutrient-poor waters of Canada and the northern U.S. and Europe that has become invasive in warmer waters where it forms large, thick brown, yellow, or whitish mats attached to a submerged substrate (such as a rock or plant) All visitors, especially boaters and fishermen, are being encouraged to wash their gear in an effort to avoid spreading didymo. — Sean Sauro … the unpleasant and unwanted freshwater algae, Didymophenia geminata, commonly called didymo, or, with absolutely no trace of affection, rock snot. — James Gorman —called also rock snot

Origin and Etymology of didymo

short for New Latin Didymosphenia, genus name (earlier, name for a subgenus of Gomphonema), from Greek dídymos “double,” (in plural) “twins” + -o- -o- + sphḗn “wedge” (of obscure origin) + -ia 1-ia; so named for the symmetrical wedge-like nodes at each end of the raphe — more at didymium

First Known Use: 2005

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