A container candle is just that...a candle that is poured/made in a container. But it is different from a votive (that is put into a container) in that the mold and the container are the same thing. The candle is poured into the container.
Votive candles are among the most used candles of any type. They're actually a hybrid between a pillar candle and a container candle in that, before they're burned, they're free-standing, usually cylindrical candles (just like a pillar,) but once they're lit, they generally melt completely enough to take the shape of the votive holder that they're placed in (like a container candle.)
Pillar candles are a type of molded candle. The wax 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.