This is the 17253rd most frequent Korean word.
서점이
"서점이" means "bookstore" (subject marker attached).
The word "서점이" functions as the subject here, referring to the bookstore that is performing the action of opening.
서점이 문을 열었어요.
The bookstore has opened.
In this sentence, "서점이" is the subject describing the bookstore's characteristics.
서점이 아주 크고 깔끔해요.
The bookstore is very large and clean.
Here, "서점이" serves as the subject referring to the location of the bookstore.