Twinship

[Oralee]

When two people who are not related share literally almost everything in common, and are better than best friends with each other.

[Lanell]

having a best friend who could pass as your twin. not necessarily an identical twin, could be fraternal. finishing each others sentences, watching the same tv show at the same time, thinking the exact same thing, having interest in the same things, are all signs of twinship.