Hoar Frost

We were out early (for us) this morning and observed another gorgeous frost. My dad has referred to it as a Hoar Frost. According to Wikipedia the definition is: Radiation frost (also called hoar frost or hoarfrost) refers to the white ice crystals, loosely deposited on the ground or exposed objects, that form on cold clear nights when heat losses into the open skies cause objects to become colder than the surrounding air.