A more thorough explanation:

A normal college, also known as a normal school, is a training institution for individuals who want to become public-school teachers. These schools were first established in the United States during the 1800s and were initially two-year programs for elementary-school teachers. However, over time, they expanded into four-year teaching colleges that offer a wider range of education and teaching programs.

For example, a student who wants to become an elementary-school teacher may attend a normal college to receive the necessary training and education. The curriculum would include courses on teaching methods, child development, and classroom management, among others. Upon graduation, the student would be qualified to teach in a public-school setting.

Normal colleges have played a significant role in shaping the education system in the United States by providing a steady supply of qualified teachers. Today, many of these institutions have evolved into liberal arts colleges that offer a broader range of academic programs.