I think we use the term in to mean different things. For instance, on one hand I might say, "I have faith in Bill", meaning that I think I see certain qualities in him and that I believe Bill will live up to that potential. I might even go to bat for him.
Or in a religious sense we say, "What is your faith?", the answer being Buddist, Muslim, Christian, whatever, an alignment with a certain belief system or tradition.
Or finally, the word 'faith' can stem from Paul's comment that "If Jesus were not resurrected from the dead we (early Christians) are, most among men, to be pitied." He was saying, I think, that faith in Jesus has nothing to do with believing he existed, was executed, or was resurrected. Those were contemporary events to Paul and to the readers of that letter, matters of actual fact rather than belief, and could be easily verified by questioning some of the hundreds of eyewitnesses who existed. These events occurred in broad daylight in front of the public, and the first church grew by asking people to understand what they had actually seen. (Acts 2)
Therefore, one might choose to believe that those events actually existed, but this a matter of history rather than faith. Instead, in this case faith seems to be what one chooses to do with what he/she knows to be true.
I visited the Sears Tower in Chicago a few months ago. Near the top, 103 floors up, are small glass observation boxes that jut out over the city. Glass walls, glass floor. You literally step out onto what appears to be nothing. It is a horrifying experience. Or exhilarating, or both. But many people simply cannot do it. You just cant make yourself walk out there. Everyone knows it is safe; this is not in question. But some people are too motivated by past experience or fear to let themselvs do it. Others, also with hesitation, do it. The facts are the same either way, but only some choose to experience it.