buttercup
noun
but·ter·cup
| \ ˈbə-tər-ˌkəp
\
\
plural buttercups
Definition of buttercup
: any of a large genus (Ranunculus of the family Ranunculaceae, the buttercup family) of chiefly perennial herbaceous plants having colorful cup-shaped flowers with 5 or sometimes many petals : ranunculus
especially
: a plant (such as R. acris and R. repens) with usually bright yellow, five-petaled flowers
The flowers …, 1 1/2-in.-wide golden buttercups set atop a green topknot of fringy leaves, are very bright and cheery in the chill of March. — Aileen Detter Rodgers
— compare crowfoot, spearwort