Faith is the substance of things hoped for, the evidence of things not seen.
Is this a full Biblical definition of Christian faith? I have thought not, believing it to be merely a descriptor, like saying, "A banana is yellow," is not a full definition but only a partial descriptor of what constitutes a banana. Perhaps I am wrong about that, but it seems to me, perhaps because sometimes (non-believing) people used to point to that Scripture verse to claim we believe without evidence... yet I have faith because I have experienced within my own self the presence of God and His workmanship in my life, and those experiences went a long way to moving me toward a full-blown faith, when all else made no sense. I could not believe simply because I was born into and raised in a "Christian" home, or because I was told to, or "brainwashed" as the heathen likes to clam (LOL). The issue of whether or not God existed became a persistent consuming direction I walked in life, even as I was in fairly full rebellion toward what I now know and understand to be the One True God. In other words, the Biblical promise of, "If you seek, you shall find," became a reality for me. God knows we are not seeking Him... and yet if we seek truth and meaning and purpose in our lives beyond what can be seen with the eye and/or divulged by observation and/or scientific inquiry, we will find the embodiment of Truth in Jesus Christ, Who is Himself the Truth.