Catholicism is a denomination, hence a subset, of Christianity.<quoted text>
BTW, Anglicans do most of the above and are Protestant.
I know, I know...you're also not Anglican.
All Catholics are Christians, but not all Christians are Catholics.
A Christian refers to a follower of Jesus Christ who may be a Catholic, Protestant, Gnostic, Mormon, Evangelical, Anglican or Orthodox, or follower of another branch of the religion.
A Catholic refers to a Christian who follows the Catholic religion as transmitted through the succession of Popes of Rome and the Vatican Empire across history.
The Pope is the leader of the Catholic church. The Catholic Church is the largest of the Christian Churches - about 60% of Christians are Catholic.