A schoonmoeder is a mother-in-law. In older documents, the term is also sometimes used for stepmother (another type of mother-by-marriage).

Marriage of Henk Hoitink and Mien Woordes, 1942. On the left, his new mother-in-law, Janna Geertruida Droppers.

In researching my great-grandparents, I see that someone in the Netherlands has used my info on them. That is good but I do not know which relative they are most interested in. Are the last names “Ballard” and “Anglen (Anglin)” distinct Dutch names?
Thank you.
Steve