This is the type of question that quickly and easily results in a lot of toes feeling like they're being stepped on. Thus, a quick, and hopefully fairly agreeable answer:
The term can be used either improperly or properly.
I. Improperly and commonly it is used in a minimal sense to refer to 5 specific aspects or elements of a soteriological schema. Specifically, the "Calvinist" or Reformed correction at Dort of 5 improper teachings propagated by the Remonstrants.
II. Properly but rarely, it is a (perhaps unfortunate) synonym for "Reformed," which involves a comprehensive system of doctrine, as well as a piety and practice. I say "perhaps unforunate," as it is not to Calvin as the head of an interpretive school that we look, but rather a large group of teachers, including at the head (among others) Calvin, Bullinger, Zwingli, Bucer, Melanchthon, Musculus and Vermigli, as well as their theological descendants. The improper sense of the term arose when the Reformed or "Calvinists" corrected 5 teachings of the Remonstrants; and thus those 5 Points are the Calvinist position on those issues. In the broad and proper sense, however, if you want to know what it means, one simply has to read our Confessions and catechisms. That is Calvinism.