Final answer:
The default class for functions is often referred to as the main function or the function class.
Step-by-step explanation:
The default class for functions in programming is often referred to as the main function or the function class. This is the starting point of a program and where the execution begins. In languages like C, C++, and Java, the function class is typically defined as 'void main()'. In Python, it is commonly referred to as 'def main()':
def main():
# code goes here
if __name__ == '__main__':
main()