Originally "Calvinism" was used by Lutherans to refer to Calvin's teaching regarding Communion. I believe the term should refer to doctrine that distinguished Calvin's denomination from other Reformed churches and doctrines of that trajectory (Calvin's view of communion; Penal Substitution Theory; the Five Points of Calvinism; the nature of Christ's suffering; etc.). Obviously things spread out and change (for example, Dispensationalism was at first popular only among Calvinists). I guess I'd say the real Calvinists today are Presbyterians.Again, and I'm sure I posted this somewhere...
I'm not sure what a "Calvinist" is, since I've never run across anyone who adheres strictly to the teachings of John Calvin.
I do know people, and even whole churches, that adhere strictly to the teachings of John Wesley, and they're called "Wesleyans" and "Methodists".
But, since people would label me as such, this is the reason I am saved:
" Blessed [be] the God and Father of our Lord Jesus Christ, who hath blessed us with all spiritual blessings in heavenly [places] in Christ:
4 according as he hath chosen us in him before the foundation of the world, that we should be holy and without blame before him in love:
5 having predestinated us unto the adoption of children by Jesus Christ to himself, according to the good pleasure of his will,
6 to the praise of the glory of his grace, wherein he hath made us accepted in the beloved." ( Ephesians 1:3-6 )
Around here a "Calvinist" is typically someone who affirms a certain number of the points of Calvinism (or the "Doctrines of Grace"). It's usually restricted to soteriology and the Calvinistic answer to the five articles. Personally I do not see how one can be anything but a five point Calvinist (the logic is clearest when seen through the whole defense).
I don't like that definition because I affirm all five points but am definitely not a Calvinist.