ˌone anˈother S3 W3 pronoun
each other:
Liz and I have known one another for years.
They often stay at one another’s houses.

[TahlilGaran] Dictionary of Contemporary English ▲

one another
pronoun
BAD: The children get on well one another.
GOOD: The children get on well with one another.
BAD: They had good opinions one another.
GOOD: They had good opinions of one another.

Usage Note:
See also EACH OTHER (each other)

[TahlilGaran] Dictionary of Common Errors ▲

one another
{pron.} Each one the other; one the other.
That man and his wife love each other.

Bill and Mary gave one another Christmas presents last year.

All the children at the party were looking at one another trying to recognize one another in their masks and costumes.

The birds fought each other over the bread.

[TahlilGaran] English Idioms Dictionary ▲