This is the 5060th most frequent Korean word.
꼬리가
"꼬리가" means "tail" in English.
Here, '꼬리가' (the tail) is used as the subject of the sentence, indicating possession ('고양이의', of the cat).
고양이의 꼬리가 바닥을 스쳐 지나갔다.
The cat's tail brushed against the floor.
In this sentence, '꼬리가' (the tail) functions as the subject of the action ('흔들렸다', wagged).
행복한 강아지가 꼬리가 빠르게 흔들렸다.
The happy puppy's tail wagged quickly.
In this expression, '꼬리가' (the tail) metaphorically refers to a continuation or extension of the story.