"Protestantism was the triumph of Paul over Peter; fundamentalism is the triumph of Paul over Christ."— Will Durant
Let me just add that the term Christian Fundamentalist when bandied about by those outside the fold (only God knows Will Durant's heart) is always off the mark. Today, it is frequently used by those on the left to compare a so-called Christian Fundamentalist to the Taliban. Christian fundamentalism is a family quarrel within Protestantism, especially within American Protestantism.
Historically, the roots of this term are found in the late 19th century when a group of pastors and theologians penned a series of essays to define a position against the theological liberalism of the day. The essays were published in 12 volumes under the title "Christian Fundamentals".
Today, the term fundamentalist is understood within what I will call mainstream evangelical Protestantism as those Protestant Christians who practice stricter life-style rules: no drinking, smoking, dancing, etc.