That Infamous "F" Word...what does it really mean?

Throughout my life, I've had to ponder over the word friendship and what does it really mean. I consider myself a good friend...not the best all the time but overall, I think I'm a great friend. I realize that in order to gain good friends, you have to be one yourself and that's something I work on daily. I know that true friendships will experience good & bad times but if its true indeed, it will stand the test of time.
Every now and then, I'm brought to question friendships, both old & new. I have a circle of friends who are like a second family to me. Some of them I've known almost all my life and some that I've just become friends with in the last 5 years of my life. But no matter the duration, when I say that someone is my friend, I mean it. Recently, I've been challenged with that "F" word once again and it has lead me to question, what is friendship?
According to Wikipedia, friendship is, "a term used to denote co-operative and supportive behaviour between two or more humans; connotes a relationship which involves mutual knowledge, esteem, and affection. It also states, "their tastes will usually be similar and may converge, and they will share enjoyable activities. They will also engage in mutually helping behavior, such as exchange of advice and the sharing of hardship. A friend is someone who may often demonstrate reciprocating and reflective behaviors. Yet for many, friendship is nothing more than the trust that someone or something will not harm them. Value that is found in friendships is often the result of a friend demonstrating on a consistent basis:the tendency to desire what is best for the other; sympathy and empathy; honesty, perhaps in situations where it may be difficult for others to speak the truth and mutual understanding.
From the definition, I clearly understand what the "F" word is and I do believe that my friends and I share in all of these things. But a recent experience with a friend has lead me to once again question the "F" word. So I ask, what do I do now? Do I confront this person about what I'm feeling; do I act as if she doesn't exist anymore; do I smile in her face as if nothing has happened...I don't know what to do cause once again, this person has lead me to question the "F" word once again. My question to myself is...what lengths am I willing to go to salvage a friendship and for that matter, is it really worth it? So that infamous "F" word, once again has resurfaced in my mind...an unfortunate experience with a person who I consider a good friend has caused me to question the meaning. So, to all my friends who truly love me, has my back through thick & thin(even when I'm difficult to deal with), celebrates all my acccomplishments & listens & crys with me through all my adversity, who uplifts me when I'm down, who doesn't envy me, who checks on me when I'm sick, who will fight my battles if anyone comes against me, who will put someone in their place if they speak a bad word about me, who prays for me & my family....thanks for showing me what the "F" word really means. I LOVE U GUYS!!!! For anyone who's reading this & smiling, then you know the true meaning of the "F" word...don't ever be the reason for someone who calls you a friend to question the true meaning of friendship...your actions should prove to them that no matter what...you know & understand the true meaning of the "F" word.