Black ice, sometimes called clear ice, refers to a thin coating of glazed ice on a surface.

While not truly black, it is virtually transparent, allowing black asphalt/macadam roadways to be seen through it, hence the term "black ice". The typically low levels of noticeable ice pellets, snow, or sleet surrounding black ice means that areas of the ice are often practically invisible to drivers and thereby do not serve as a good indicator that they should reduce their speeds.

Similar thin invisible layers of ice that form along ships can cause them to become unbalanced. In the mountains, black ice is referred to as verglas (glaze ice) and is a great hazard for climbers.