I work under a the name Sous sherpa, but I write it as one word; Soussherpa.

Does this count as a pseudonym even though I deliberatly
write both words as one word?

Is it a Nom de plume? (I don't know if I spelled that right)

Can it be called any kind of "pen name", so to speak?

Your help will be much appreciated.

Quick answer:

It is your pen name.
It is your pseudonym.
It is your nom de plume.


Longer answer:

NOM DE PLUME is French for 'name of the pen'. It is another term for a pen name or pseudonym. It is a fictitious name used by a writer to conceal identity. For example, Samuel Clemens used the nom de plume Mark Twain, and Mary Ann Cross used George Eliot (to conceal that she was a she). I would point out that although French, it is not used by the French. They would use nom de guerre.

So there is no problem.