Dictionary.com
Thesaurus.com

grass-of-Parnassus

American  
[gras-uhv-pahr-nas-uhs, grahs-] / ˈgræs əv pɑrˈnæs əs, ˈgrɑs- /

noun

  1. any plant belonging to the genus Parnassia, of the saxifrage family, growing in marshy areas, having broad, smooth leaves and a single, pale flower.

grass-of-Parnassus British  

noun

  1. a herbaceous perennial N temperate marsh plant, Parnassia palustris, with solitary whitish flowers: family Parnassiaceae

"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

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.