Re any other non-ignorant people tired of people saying Catholicism is not Christian?

I mean seriously its so stupid! What id the definition of a Christian? Well according to dictionary.com it is.. "pertaining to, believing in, or belonging to the religion based on the teachings of Jesus Christ" Do you people disagree with that definition? Because the definition of Catholicism is "Of or relating to the universal Christian church" and "denoting or relating to the entire body of Christians, esp to the Church before separation into the Greek or Eastern and Latin or Western Churches" So knowing what you know now, please tell me what characterizes a christian and why I am not concidered one?