Step 1 : Introduction to the question "By what word was the autumn season known before the 16th century?"
Before the season between summer and winter was "autumn" or "fall," it was a time called "harvest." It was common to call the season autumn in English in the 12th century. In the 14th century, the practice of calling the season "autumn" or "fall" spread. It isn't clear where the habit of naming the season "fall" originated but most think it came from the idea of trees shedding their leaves. "Fall" as the name of the season made its way to the New World in the 17th century and remains the preferred season name in the U.S. Source: MentalFloss.com