Stepmother-in-law

A stepmother-in-law is the stepmother of one's spouse. The children of the stepmother-in-law would be the person's stepbrothers-in-law and stepsisters-in-law.

Stepmother-in-law

A stepmother-in-law is the stepmother of one's spouse. The children of the stepmother-in-law would be the person's stepbrothers-in-law and stepsisters-in-law.