buttercup
noun
but·ter·cup ˈbə-tər-ˌkəp 
plural buttercups
: 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 Aileen Detter Rodgers 
Example Sentences
Recent Examples on the Web Sofia executed all her bridesmaid duties perfectly, from smiling big in identical buttercup yellow gowns to 'gramming the cake-cutting moment to actually eating the cake to bringing the hottest date. Alex Apatoff, Peoplemag, 8 Aug. 2022 Inside could be two deep orange yolks or a single one as fat and yellow as a buttercup. Ruby Tandoh, Bon Appétit, 13 July 2022 An Easy-Bake Oven has more gravitas than this thing, which comes in colors including buttercup-yellow and baby blue and plays an obnoxious, twinkly little ditty when it is done. Rachel Syme, The New Yorker, 2 June 2022 This park features a buttercup, misty mountain, ground spray, three ants, corn poppy, flutter, morning cross and three surf stones. Shanti Lerner, The Arizona Republic, 26 May 2022 As the lighting at the venue bathed the space in pleasing shades of buttercup, peach, lavender, sky blue, and sea foam green, models walked with the languid stride of ’70s greats. Alison S. Cohn, Harper's BAZAAR, 16 Feb. 2022 As a reminder, lesser celandine (Ficaria verna) is an invasive spring ephemeral perennial plant, also known as fig buttercup, which has become more prevalent in home garden beds and lawns. Tim Johnson, chicagotribune.com, 2 May 2021 Columbine – Aquilegia – Columbine is a cool season perennial that is a member of the buttercup or ranunculus family. Janet Carson, Arkansas Online, 12 Apr. 2021 Similar in shape to a butternut (but about half the size), this hybrid is a cross between a butternut and a buttercup. Jeanmarie Brownson, chicagotribune.com, 30 Oct. 2020 See More
Alex Apatoff, Peoplemag, 8 Aug. 2022 Inside could be two deep orange yolks or a single one as fat and yellow as a buttercup. Ruby Tandoh, Bon Appétit, 13 July 2022 An Easy-Bake Oven has more gravitas than this thing, which comes in colors including buttercup-yellow and baby blue and plays an obnoxious, twinkly little ditty when it is done. Rachel Syme, The New Yorker, 2 June 2022 This park features a buttercup, misty mountain, ground spray, three ants, corn poppy, flutter, morning cross and three surf stones. Shanti Lerner, The Arizona Republic, 26 May 2022 As the lighting at the venue bathed the space in pleasing shades of buttercup, peach, lavender, sky blue, and sea foam green, models walked with the languid stride of ’70s greats. Alison S. Cohn, Harper's BAZAAR, 16 Feb. 2022 As a reminder, lesser celandine (Ficaria verna) is an invasive spring ephemeral perennial plant, also known as fig buttercup, which has become more prevalent in home garden beds and lawns. Tim Johnson, chicagotribune.com, 2 May 2021 Columbine – Aquilegia – Columbine is a cool season perennial that is a member of the buttercup or ranunculus family. Janet Carson, Arkansas Online, 12 Apr. 2021 Similar in shape to a butternut (but about half the size), this hybrid is a cross between a butternut and a buttercup. Jeanmarie Brownson, chicagotribune.com, 30 Oct. 2020 See More Word History
First Known Use
1688, in the meaning defined above
Kids Definition
buttercup
noun
but·ter·cup ˈbə-tər-ˌkəp
: a common wildflower with bright yellow blossoms