What does the word “Spirit” really mean?

What does it really mean to search the Lord with all your heart? We live our life out of our identity, self-image and self-worth. We can’t function well until tall three are all established in our hearts. Moving past the intellectual boundary of identity and seeing and experiencing your life “in God” as completely yours brings you to the concept of living in the spirit. What does the word “Spirit” really mean? How does the function of our “breath” relate to our spirit? Our breath is our life, and in the same way our spirit is our life.