Spirit is life, Mrrzy. (in my opinion) You are quite correct to connect it with the breath, because it is the breath, and the heartbeat, and the other cyclical repeating motions such as nerve impulses that indicate life in a living body.

Everything in the Universe seems to be founded upon oscillating waveforms of cyclical back and forth movement that are quite analagous to the breath, if you stop to think about it...and this is true right down to the atomic level. Everything vibrates or oscillates.

In a living biological creature like a human the very obvious vibrations of breath and heartbeat indicate the presence of life...and what is termed "Spirit" in the religious traditions. When the heartbeat ceases, the breathing ceases, and the nerve impulses cease, the Spirit is said to have departed the body....which is the same thing as to say: life has now left the body. The body is now lifeless.

So that's what Spirit is to me. It's life itself.

The fact that vibrations or oscillations are also found in non-biological things right down to atoms has led to some forms of spiritual philosophy that propound the theory that everything is "alive" in some sense...including all the inanimate objects. If that's the case, then they would be "alive" in a very different sense, of course, than an animal or a human or a plant is...and they probably would not possess much, if any, self-awareness or volitional capability.

They would, if so, be "alive" in a passive sense....but not as we are, in an active sense.