Can Someone Explain Preschool and Kindergarten Are Different?

Hey Everyone, I need some help from you all. My nephew has recently turned 4 years old and I am planning to send him to a good preschool but I am very confused whether preschool and kindergarten are the same or different and if they are different then which one is best for my nephew according to his age.

I request all the parents who know about this to please suggest to me.