n 1  cap  :  a genus (family Magnoliaceae, the magnolia family) of No. American and Asian shrubs and trees including some whose bark has been used esp. as a bitter tonic and diaphoretic in folk medicine  2 a  :  any shrub or tree of the genus Magnolia  b  :  the dried bark of a magnolia .
 
 
 
Published under license with Merriam-Webster, Incorporated.  © 1997-2021.