Definition of "sunflower"

sunflower

/ˈsʌn.flaʊ.ɚ/

noun
plural sunflowers
1. Any plant of the genus Helianthus, so called probably from the form and color of its floral head, having the form of a large disk surrounded by yellow ray flowers.
  Quotations
  The flowers glowed red and golden: snapdragons and sunflowers, and nasturtians trailing all over the turf walls and peeping in at the round windows.
  1954 July 29, J.R.R. Tolkien, “I: A Long-Expected Party”, in The Fellowship of the Ring (The Lord of the Rings; 1)
  1. The commonly cultivated species, Helianthus annuus, a native of America.
2. A bright yellow, like that of the flower petals.
3. (informal, organic chemistry) Any flat, radially symmetric organic compound, such as coronene.
4. (pathology) Synonym of worm-star