buttercup
n. countablen. a common yellow flower with a soft, round center that you can pop. It is often found in grassy fields and is popular in children's gardens.
n. a common wildflower of the genus Ranunculus, typically characterized by bright yellow petals and a soft, spongy center. Often used in informal contexts to refer to the plant or its flowers.
The children picked a buttercup from the field.
We spent the afternoon picking buttercups and daisies to make a bouquet for the kitchen table.
While the buttercup is often dismissed as a common weed, it serves as a vital nectar source for early-season pollinators in the spring.
From butter + cup. Both sense 1 and 2 are from the flowers' association with butter, from their yellow colour. Compare butterflower for a similar derivation; outside of English, compare Dutch boterbloem, German Butterblume.