By what name do we refer to the wave of religious fervor which swept the nation in 1800s?

Answer: The Second Great Awakening

Explanation: In early American colonies, The First Great Awakening happened in the middle of the 1700's. Then later, another wave again became very popular, known as The Second Great Awakening. It was a time of noticeable reform as more Americans looked at Christianity differently, more fundamentally. There was more of a focus on becoming a member of a Christian church, participation in mission type work and trying to spread that influence across what what happening in society at that time (such as the ban of alcohol, which was influenced by this strong view). People would also travel from far away to hear such well known preachers as Charles Finney and others who were promoters of The Second Great Awakening Christian values.