any plant of the genus Gratiola, a bitter herb used medicinally.
Also hedge-hys·sop [hej-his-uh p] /ˈhɛdʒˌhɪs əp/.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
any of several North American scrophulariaceous plants of the genus Gratiola, esp G. aurea, having small yellow or white flowers
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