Sine: A trigonometric function that relates the ratio of the length of the side opposite an acute angle in a right triangle to the length of its hypotenuse.
Inverse Function: A function that undoes another function. In this case, arcsine is the inverse function of sine.
Domain: The set of all possible input values for a given function. For arcsine, its domain is -1 to 1 since sine values range from -1 to 1.