This is the 731st most frequent Korean word.
아들
Son.
In this sentence, "아들" is combined with the possessive suffix "-에게" to indicate the receiver of the action "gave."
나는 아들에게 책을 선물로 주었어요.
I gave a book as a gift to my son.
Here, "아들" is used in its plural form "아들들" to describe multiple sons.
그는 세 아들의 아버지입니다.
He is the father of three sons.
In this case, "아들" is the subject of the sentence, indicating who performs the action "plays soccer."