彼此 (each other / one another)

Mutual, with a formal bow

• each other彼此bǐ cǐ = "each other / one another" — a touch more formal than each other互相hù xiāng.
• each other彼此bǐ cǐto understand了解liǎo jiě = "understand each other."
• each other彼此bǐ cǐ can also stand alone as a noun ("each other").

each other彼此bǐ cǐ + Verb

• each other彼此bǐ cǐ marks a mutual, two-way relationship.

we我们wǒ meneach other彼此bǐ cǐtrust信任xìn rèn。

• each other彼此bǐ cǐto trust信任xìn rèn = "trust one another."

Recap

Read the full reference: HSK 5 grammar — Nouns.