coordinate system - Difference between WGS84 and EPSG:4326?

What is the difference between WGS84 and EPSG 4326?

It seems like for a given dataset it might be both WGS84 and EPSG:4326.

Answer

4326 is just the EPSG identifier of WGS84.

WGS84 comprises a standard coordinate frame for the Earth, a datum/reference ellipsoid for raw altitude data, and a gravitational equipotential surface (the geoid) that defines the nominal sea level. [WP]