be closely linked; share the same breath; to have interests or feelings that are intimately connected

To have shared traits or a connection between two or more distinct things

to have exhaled and inhaled air pass through to one another; to be interconnected by breathing

to help each other out with what one has and the other lacks; to reciprocate with material or financial assistance among friends

Two people being so closely aligned in thought or feeling that they can sense each other's mind; having a mutual understanding or telepathic connection