The term that can effectively replace "the first day of the Chinese New Year" in English is the "Spring Festival." This term is widely recognized and used in the United States to refer to the most important traditional holiday in China. The Spring Festival, also known as the Chinese New Year, marks the beginning of the lunar new year and is celebrated with a variety of customs and festivities.

The reason for using "Spring Festival" instead of "the first day of the Chinese New Year" is multifaceted. Firstly, it is a more inclusive term that encompasses the entire holiday period, which typically spans from the first day of the new year to the Lantern Festival, which usually falls on the 15th day of the first lunar month. This broader term reflects the comprehensive nature of the celebration, which includes family reunions, feasts, and various cultural activities.

Secondly, "Spring Festival" is more easily understood by non-Chinese speakers. The term "Chinese New Year" is also commonly used, but it can sometimes be confused with other New Year celebrations around the world. By using "Spring Festival," there is less likelihood of confusion, as it specifically refers to the Chinese New Year.

According to a survey conducted by the Pew Research Center in 2019, approximately 1.9 billion people celebrate the Chinese New Year worldwide. In the United States, the Chinese New Year is celebrated by a significant number of Chinese Americans, as well as by people of other ethnic backgrounds who appreciate and participate in the holiday's cultural and social aspects. The use of "Spring Festival" as a replacement for "the first day of the Chinese New Year" helps to promote a deeper understanding and appreciation of this important cultural event among the American public.