Definition of substitution. 1  1a : the act, process, or result of substituting one thing for anotherb : replacement of one mathematical entity by another of equal value. 2  2 : one that is substituted for another.
Homogenized milk is any sort of milk that has been mechanically treated to ensure that it has a smooth, even consistency. The homogenization process typically involves high temperatures, agitation, and filtration, all aimed at breaking down milk's naturally occurring fat molecules.
Evaporated milk is a milk product, usually sold in cans, that is made by removing about 60 percent of the water from ordinary milk. Evaporated milk can be made from both whole milk or skim milk. In either case, the milk is homogenized and then the water is removed by gently heating it. The evaporated milk product is sealed in cans which are then heated to kill any bacteria in the milk.