What does “complex” refer to in the C language?

In C language, complex is a data type used to represent complex numbers. Complex numbers consist of a real part and an imaginary part, which can be represented using the complex data type as “real + imag * i”, where real is the real part, imag is the imaginary part, and i is the imaginary unit. C language provides various functions and operators for manipulating complex numbers, such as addition, subtraction, multiplication, and division.