kingcup vs cowslip

kingcup and cowslip both are nouns.

Word	Noun	Adjective	Verb	Adverb
kingcup	Yes	No	No	No
cowslip	Yes	No	No	No

As nouns, kingcup and cowslip are synonyms defined as:

kingcup and cowslip: swamp plant of Europe and North America having bright yellow flowers resembling buttercups

Other synonyms of kingcup include Caltha palustris, marsh marigold, May blob, meadow bright, water dragon.

kingcup (noun)	cowslip (noun)
any of various plants of the genus Ranunculus	early spring flower common in British isles having fragrant yellow or sometimes purple flowers
swamp plant of Europe and North America having bright yellow flowers resembling buttercups	swamp plant of Europe and North America having bright yellow flowers resembling buttercups