Philia

Etymology

Greek "philia" meant friendship or fondness, and Aristotle devoted two books of his Ethics to it as the bond of a good life. It is the "-phile" in every enthusiasm and the "phil-" in "philosophy," love of wisdom, and in Philadelphia.

noun · /FIL-ee-uh/
Warm affectionate love between friends or equals.
What it names
The loyal, reciprocal bond of friendship, distinct from both desire and duty.
Example
What held the old band together was less ambition than philia — a durable affection that survived the arguments.
Related idea
The friendship-love among the Greek loves; its root drives bibliophile and, sociologically, homophily, our pull toward those like us.