I agree with the others. It is because they resemble the sun and it turns to face the sun.
Thank you Kimberly for your answer. I thought so as much
They are amazing aren’t they!
They both look like the sun and always turn to face it 😊 I suppose either or both could be the reason for their name.
You are very right Cheryl. Thanks so much for your answer.
It may be because of their characteristic behavior of turning their heads to follow the sun.
I thought so too. Thanks so much Maria for your answer.
Yes it is because it resembles the sun it has a Greek origin in its history of naming.
Thanks so much Catherine for your answer. Yes it does resemble
The sunflower gets its name from the Greek words helios meaning “sun”, and anthos, meaning “flower” The name also refers to the flower’s appearance, which resembles the sun with its round flower heads and ligules.
Thank you so much for your detailed answer. Have you watched the sunflower during the day. I really found this fascinating. What I observed is they always face the direction of the sun.So I thought that could be the reason they are called sunflower. I guess I am wrong.
You’re welcome Virginia

Thanks for your answer Jason. I thought so too.