• 入はいる — to enter
• 入はいれる — to insert; to put in
• 入口いりぐち — entrance
• 入学にゅうがく — school admission
• 輸入ゆにゅう — import
• 入院にゅういん — hospitalization

The shape of “入” originally represented a person entering through a doorway. It carries the ideas of going in, inserting, or becoming a part of something. You’ll see it frequently in words about admissions, directions, and action-related verbs.

この部屋へやに 入はいってください。
Please enter this room.

お茶ちゃを 入いれましょうか？
Shall I pour some tea?