Exactly that

MMN - mother's maiden name.
Women's maiden names have an important place in Scottish research. Married women never legally lose the right to use their maiden name which is why the maiden name features so prominantly on documents.
For example, when searching for a death of a married woman in Scotland, both surnames are recorded on the registration (along with her parents' names, including her mother's maiden name...and so on

). Married women will often be referred to as, for example, Mary Thomson or Johnson.
Scotlands People are undertaking a major indexing programme to include the deceased person's mother's maiden name. It is a really useful search aid that will help enormously in narrowing down search results on the index page. Look forward to seeing it completed. As always though, the details are only as good as remembered by an informant to a death

Monica