A real quick one...
Faith: As my left and right brain experience a great back and forth game of mental volleyball, the best definition they seem to agree upon is this:
'Trusting in what you can't see, regardless of what you can see'.
Faith comes from a steadfast belief in what we feel, not in what we see. In many cases, we have no evidence to support what we feel, because the evidence we search for does not exist. Therefore proof is needless and in fact won't exist in a life built on faith.
Besides evidence, another word that plays a role in faith is reason. To operate on faith, one merely has to shut the eye of reason, limiting the effects of fear. Fear causes doubt, and doubt undermines the very foundation faith was built upon. Faith is bigger than fear!