mutually; with each other; reciprocally
Used when two or more parties do something to or with each other. Often interchangeable with お互いに, but 互いに is slightly more formal or written.
See also: お互いに
私たちは互いに助け合うべきだ。
We should help each other.
The two looked at each other.
We helped each other.
A married couple should respect each other.
The two countries compromised and reached an agreement.