This is the 2532nd most frequent Chinese word.
炎
"炎" means "flame," "blaze," or "inflammation."
炎热 is used here as an adjective to describe the hot weather.
天气炎热，人们喜欢去海边玩。
The weather is hot, people like to go to the beach.
发炎 is used here as a verb indicating that the throat is inflamed.
他的嗓子发炎了，需要吃药。
His throat is inflamed, he needs to take medicine.
炎 is used here as a proper noun, referring to a historical figure Yan from Chinese mythology.