pronoun
Etymology: Middle English ech other, from Old English ǣlc ōther, from ǣlc each + ōther other
: each of two or more in reciprocal action or relation : one another — used especially in the possessive case or as the object of a verb or preposition to indicate that of the two or more persons or things referred to by two or more substantives or by a plural or collective substantive any particular one performs the same action upon or stands in the same relation to one or more of the others as one or more of the others do to him
army officers salute each other
when he and I saw each other's faces
the two are now writing to each other daily
— sometimes used with only other in the possessive case or as the object of a verb or preposition and with each in a different construction typically as subject of a verb or in apposition with the subject of a verb
each at other looked — John Keats
each for other they were born — R.W.Emerson