mutually; with each other; reciprocally
Polite adverbial form of 互いに, used when two or more parties do something to or for each other. Often implies a cooperative or reciprocal action.
See also: 互いに
お互いに助け合いましょう。
Let's help each other.
We decided to keep in touch with each other.
Let's help each other out when we're in trouble.
Let's both be careful not to catch a cold.
It's important to talk things through and understand each other.