noun, noun which may take the genitive case particle 'no', adverb
each other; one another
Polite version of 互い; used as a noun, with の, or adverbially to express mutual action or relationship.
See also: 互い
お互いの意見を尊重しましょう。
Let's respect each other's opinions.
困ったときはお互い助け合うものだ。
When in trouble, we should help each other.