What is the difference between?
놀이터 and 운동장

자동차 and 자가용

어른 and 성인

Question

What is the difference between?
놀이터 and 운동장

자동차 and 자가용

어른 and 성인

Answer

- 놀이터 is for children, while 운동장 is..... well 運動場

- 自動車 vs 自家用. I hope you understand better now as a Japanese.

- 성인(成人) is more of a legal term while 어른 means adult in general.

Answer

- 놀이터: 놀이(play, game) + 터 (ground, space).  Playground (for children).
- 운동장: 운동(exercise, sport) + 장(ground, lot).  Exercise and sports ground (in schools and public parks, etc)

- 자동차: 자동(auto) + 차(vehicle).  Automobile in general.
- 자가용: 자가(self) + 용(usage).  "Private usage" (automobile, boat, airplane, etc).
Ex:  자가용 차:  private car,  자가용 비행기:  private airplane.

- 성인: adult. Technical/legal term used in statistics, law, etc.
- 어른: adult. General term.  Also has another meaning: a respected elder.