Name given to 180 degree longitude line?

The 180 degree longitude is often miscalled international date line, when it is actually called the Anti Meridian.

The date line is not a meridian or line of longitude because it is not a straight line as it deviates to separate geographical places, certain island groups for instance.

See the link below for an image.

The longitude that runs through Greenwich England is the prime meridian, which is 0 deg longitude.