What are the differences between a Christian and a Catholic?

The word "Christian" means "little Christ," and is attributable to any religion or denomination that considers itself to be following Jesus Christ or his teachings. Since Catholicism falls into the category of religions that adhere to the teachings of Jesus Christ, technically a Catholic is a Christian, but not all Christians are Catholic.

The word "Catholic" means "universal" and in many of the recitations of the Catholic church (and other traditional churches, such as the...

The word "Christian" means "little Christ," and is attributable to any religion or denomination that considers itself to be following Jesus Christ or his teachings. Since Catholicism falls into the category of religions that adhere to the teachings of Jesus Christ, technically a Catholic is a Christian, but not all Christians are Catholic.

The word "Catholic" means "universal" and in many of the recitations of the Catholic church (and other traditional churches, such as the Lutheran church) the word is not capitalized. The reason for this is that although "Catholic" and "catholic" are the same word, the capital "C" d the specific church, and the lower case "c" d the universal church, or the unified family of God. 

To interpret your question slightly differently, I might phrase it, "What are the differences between a Protestant and a Catholic?" Protestant Christians are the major branch of Christianity that is non-Catholic. The Protestant Reformation began in 1517 when Martin Luther published his "95 Theses," a list of disagreements or protests against the Catholic church. This spurred a split in the church that ended up creating a second branch of Christianity: Protestantism (from the word "protest").

The way this works out in the differences in beliefs in the present is that Catholic Christians place a much larger emphasis on tradition, and Protestant Christians typically believe that the sole standard of spiritual authority is the Bible. Since there are so many Protestant denominations with so many differing beliefs, it is difficult to pinpoint a list of differences between Protestant Christians in general and Catholic Christians. The teachings of the Catholic Church are published and uniform across all of their parishes.

A good source on the teachings of the Catholic Church is the United States Catholic Catechism for Adults, published by the United States Conference of Catholic Bishops, Washington, D.C., (2006). For specifics on the different Protestant denominations, you would have to look up the various denominations by name.