Definition of "each other"

Now we plunged into a deep shade with the boughs lacing each other overhead, and crossed dainty, rustic bridges over the cold trout-streams, the boards giving back the clatter of our horses' feet: or anon we shot into a clearing, with a colored glimpse of the lake and its curving shore far below us.

1897 December (indicated as 1898), Winston Churchill, chapter VIII, in The Celebrity: An Episode, New York, N.Y.: The Macmillan Company; London: Macmillan & Co., Ltd.

There is an hour or two, after the passengers have embarked, which is disquieting and fussy. […] Passengers wander restlessly about or hurry, with futile energy, from place to place. Pushing men hustle each other at the windows of the purser's office, under pretence of expecting letters or despatching telegrams.

1915, G[eorge] A. Birmingham [pseudonym; James Owen Hannay], chapter I, in Gossamer, New York, N.Y.: George H. Doran Company

We've known each other many years, but this is the first time you ever came to me for counsel or for help.

1972 March 14, Mario Puzo, Francis Ford Coppola, The Godfather, spoken by Vito Corleone (Marlon Brando), Paramount Pictures

It was the first time United had conceded six goals at Old Trafford since 1930, when Huddersfield won 6-0 and Newcastle 7-4 within four days of each other.

2011 October 23, Phil McNulty, “Man Utd 1-6 Man City”, in BBC Sport