On the other hand, they often use the prefixes dys- and a-. Dysphasia and aphasia, dyslexia and alexia. (Although if you write the last one with a capital, it can also refer to a Princess)

A quote I found:
The English affix dys- signifies a partially lacking ability whereas the a- is a complete absence of that ability.

Dys- and a- are like dis- and un- here. I am disabled, not unable(d).
Disorder, not unordered.
Disaffect, not unaffect
Disclosured, not uncoloured

Just remembered one of those what-not-to-do's. If a person uses a word to describe a part of themselves, don't tell them off for it unless it's an inappropriate word. But my English teacher told me she felt "Stump" was an awful word and she'd really prefer if I didn't use it.
Seriously? What the heck is wrong with that woman? She's also asked to pet my wheelchair, and that was after I told her I prefer she not touch me (she was using my shoulder as a handrest). She said she was sorry but was just a touch-y person (none of our class ever noticed that because she never touched anyone) and then moved her hand to my armgrip and asked to pet my wheelchair. :| But I imagine you all have enough sense not to do that, so this is a funny/disturbing anecdote only.

The naming part, though. If you don't like the word 'Stump' you don't have to use it, just call it something else. And if we're friends or partners and spending lots of time together, we can discuss it. And after the discussion maybe you'd be more comfortable with the word, or we might call it something else, or both.
But no teacher has the right to tell me I use an awful word and should use something different when I am using a normal, non-offensive word to refer to a body part that's not genital. 'Stump' is not a dirty word or a curse word (Although an occasional curse-at word..).