'Shelled' vs. 'deshelled'

[edited to reflect corrections in the comments]

It appears that shell came first, on the idea that if you were shelling something, you'd be more likely to be removing the shell than putting it on.

Though it's not found in the Oxford English Dictionary or Merriam-Webster, Dictionary.com does list de-shell as a related form to shell (transitive verb), and one can see by a search engine that deshell and de-shell are in some use.

I suspect that people use deshell because it reasonably fits the meaning of to remove the shell from – independently of shell (transitive verb), perhaps in environments where shell (transitive verb) is not used very frequently. Although at first glance it seems that they should be antonyms, by historical reasons they are used to mean the same thing.

From looking at the dictionaries, shell seems to have more prestige than deshell. By some loose Google searches, it appears that shell is more widely used than deshell.

"Shelling" is the process of removing the shell/husk/pod from a nut or vegetable. I don't think that there is such a word as "deshell", but if there is, it means the same thing...sort of like "flammable" and "inflammable". They are not really ambiguous, just confusing.

The difference is that deshelled is not a word. To shell a pistachio (or something else with a shell) is to remove the shell, so a shelled pistachio has had its shell removed.

"Shelling," in the context of nuts and seed pods, is the act of removing the shell or husk.

In a software context, however, the act of removing the shell of a program could be "deshelling," as a nonce coinage. If your beach was littered with seashells and you wanted to remove them, you might "deshell" the sand.

So the word is possible, but only in special cases.