Pillar candles are a type of molded candle where the wax (when cool) is rigid enough to burn free-standing (on a heat-resistant plate or pan.) If it is wicked correctly, it should burn evenly and not drip very much wax onto the plate. The most common pillar candles are cylindrical, and come in sizes from 1" to 4" and even larger. (At a trade show, I once saw a pillar candle that stood over 3' tall and was over 12" in diameter!)They also come in square, egg-shaped, star-shaped, triangular and other basic shapes.