each other

WordReference Random House Learner's Dictionary of American English © 2025

ˌeach ˈoth•er, pron. 

1. Pronouns each the other;
   one another:
   [used as an objectect to refer to the subject] Those two love each other.

Usage

Some guides to usage advise that each other should be used when the subject referred back to is two persons or things; one another should be used to refer back to three or more or an indefinite number. In standard practice, however, these expressions are used interchangeably, without distinction as to number.

WordReference Random House Unabridged Dictionary of American English © 2025

each′ oth′er, 

1. Pronouns each the other;
   one another (used as a compound reciprocal pronoun):
   to strike at each other;
   to hold each other's hands;
   to love each other.

• bef. 1000; Middle English; Old English. See each, other

Usage

Although some insist that each other be used only in reference to two (The two candidates respected each other) and one another in reference to three or more (The three nations threaten one another), in standard practice they are interchangeable. Each other is not restricted to two, nor is one another restricted to three or more.
The possessive of each other is each other's;
the possessive of one another is one another's.