This is the 17680th most frequent Korean word.
소년
Boy
Here, '소년' is used as the subject of the sentence, referring specifically to a male child.
소년은 공원에서 놀고 있다.
The boy is playing in the park.
In this context, '소년' is specified with the demonstrative '그', indicating a particular boy.
그 소년은 정말 친절하다.
That boy is really kind.
Here, '소년' is used in plural form ('몇 소년'), referring to an unspecified group of male children.