| accessory(noun, part, extra, addition, extension) |
| accoutrement(noun, part, extra, addition, extension) |
| accoutrements(noun, part, extension, attachment) |
| adapter(noun, part, extension, attachment) |
| add-on(noun, extra, addition) |
| addition(noun, part, extra, extension) |
| adjunct(noun, part, extra, addition, extension) |
| annex(noun, part, extra, addition, extension) |
| appendage(noun, part, extra, addition, extension) |
| appurtenance(noun, part, extra, addition, extension) |
| attachment(noun, extra, addition) |
| auxiliary(noun, part, extra, addition, extension) |
| extension(noun, part, extra, addition) |
| extra(noun, part, addition, extension) |
| fitting(noun, part, extra, addition, extension) |
| fixture(noun, part, extra, addition, extension) |
| part(noun, extra, addition, extension) |
| supplement(noun, part, extra, addition, extension) |