A reader asks about the differences between each other and one another. Editor Kory Stamper explains.
Each other and one another are both pronouns, and their uses are almost identical. Both phrases refer to one of two or more people or things that are doing something together or are in some sort of relationship with one or more members of the group. Here are some examples of use:
The kittens chased each other. = The kittens chased one another. [=each one of the kittens chased the other(s)] The members of the planning group consulted with one another. = The members of the planning group consulted with each other. [=each of the people in the planning group consulted with the other members of the group] He and I looked at one another. = He and I looked at each other. [=he looked at me and I looked at him]
Some people say that each other should only be used of two people or things and that one another is used of more than two people or things, but our evidence shows that this is not the case. If you want to observe the rule, you can, but you do not need to. You can used each other and one another the same way.
Each other and one another are fixed idioms. Do not confuse them with phrases like each of the others (which means "each one of the other people") or one and another (which can be used to indicate a choice between one person or thing and another person or thing).