There are several words (mostly related to food) which are shortenings of their historical forms. For example, the cold treat ice cream was originally known as iced cream in the 1680s. The -ed ending dropped off in about 1744.
A similar example is skim milk, which derives from the term skimmed milk which is apparently still in use in the UK. Other examples are popcorn, wax paper and whip cream.
What is the name for the historical process in which the -ed ending is dropped? Language Log talked about the phonology of this phenomenon, referring to it as t/d-dropping, but they did not give a name to the process each word went through. I was thinking that abbreviation might work, but is there a specific term available?