Assuming you are referring to the Personal word list as defined in Options->Corrections->Spelling, the list is contained in a file named wordlists.txt (older name was wordlist.ini). This file is located in
C:\Users<username>\AppData\Local\LiteratureAndLatte\Scrivener\
\AppData is usually hidden - Explorer view menu checkbox can unhide. This will allow it to be copied to a new location. Hope this helps.
See also posts Custom Words and this one.