- 童心未泯 tóngxīnwèimǐn to retain childlike innocenceTo still have a pure, childlike heart despite being an adult; to retain a sense of wonder and innocence
- 儿童心理学 értóngxīnlǐxué child psychologyBranch of psychology that studies the mental, emotional, and behavioral development of children; also explores behavioral disorders and adaptation issues during childhood.