Stepmother

n.

1.

The wife of one's father by a subsequent marriage.

Noun

1.

stepmother - the wife of your father by a subsequent marriage

dam, foster mother, genetrix, ma, mam, mama, mammy, mater, materfamilias, maternal ancestor, matriarch, mom, mommy, mother, mummy, stepbrother, stepchild, stepdaughter, stepfather, stepsister, stepson, the old woman