Evaporated milk is shelf stable milk from which about 60% of the water has been removed. It is often referred to as "canned milk," because it is sold in cans. It was popular in the early to mid 1900s because of its shelf life. It was used for infant formulas and in just about anything as a substitute for fresh milk. 

Sweetened condensed milk is also a shelf stable milk from which the water has been removed.

The difference is that a significant amount of sugar is added to the milk, which makes it useful for baking and candy making and giving it a longer shelf life.

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