A cross-denominational theological movement with the following briefs

• The Bible is the highest authority.
• Jesus is the only path to salvation
• You must go thru a conversion or the "born again" experience
• You must share your faith

Its meaning has shifted throughout Christianity's long history and changes depending on who you ask.
The religious historian George Marsden once quipped that in the 1950s and 1960s an evangelical Christian was "anyone who likes Billy Graham." But when Billy Graham was asked to define the term in the late 1980s, he replied, "Actually, that's a question I'd like to ask somebody too."
Graham isn't alone. While the word evangelical pops up in American media to describe everything from mega-churches to voting blocs, few people seem to know what an evangelical is exactly. Those who claim to know often disagree.
Source: What Does Evangelical Mean? - The Atlantic

The term brings up the image of evangelists, Preachers of tent revivals for, healing crusades, and church rallies e.g. Oral Roberts, radio, e.g. Dwight L. Moody and television e.g. Jerry Falwell, Oral Roberts, Jimmy and Tammy Bakker, Jimmy Swaggart, ...

In 2022 Michael Gerson, evangelical Christion and former speechwriter for George W. Bush, said, "There are many people who claim to be Christians in their political engagement. And one of the most basic principles of religious ethics is welcoming the stranger. I mean, how could this possibly be consistent with what we're seeing in Republican ideology right now?
I think evangelicalism has a particular problem right now. I mean, they're the people who argued, many of whom leaders argued, that character counts during the Bill Clinton years, and now character apparently doesn't count at all."
In a Washington Post Opinion column "Trump should fill Christians with rage. How come he doesn't?" Sept 1, 2022 . Gerson goes into detail about the inconsistency between Jesus and the conservative political movement.

Demographics:

• Half (49%) of evangelical Protestant adults reside in the South, which is home to 37% of the overall U.S. adult population.
• Three-quarters (76%) of evangelical Protestants in the U.S. are white, but the share of evangelicals who are not white is growing.
• 21% of evangelical Protestants (21%) are college graduates compared to 35% in the general population.

Pentecostalism
A stricter form of evangelicalism. Pentecostalism adheres to the inerrancy of the Bible and the necessity of accepting Jesus Christ as personal Lord and Savior. It is distinguished by belief in the baptism in the Holy Spirit that enables a Christian to live a Spirit-filled and empowered life. This empowerment includes the use of spiritual gifts such as speaking in tongues and divine healing—two other defining characteristics of Pentecostalism.

Books, Articles:
"The Kingdom, the Power, and the Glory: American Evangelicals in an Age of Extremism", Tim Alberta December 5, 2023

Opinion Trump should fill Christians with rage. How come he doesn’t?, Michael Gerson, Washgton Post, 2022.

Links:
Michael Gergen Following Rev. Billy Graham's death, 5 facts about U.S. evangelical Protestants | Pew Research Center
What Does Evangelical Mean? - The Atlantic
Strange Bedfellows
Worldliness Or Godliness? - Chicago Tribune