The wife of one's father and not one's natural mother.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "stepmother" in a sentence
""I'm okay with the term stepmother," said Cacho, who often blogs on her stepfamily experience."
"But Anne rejects the label "stepmother" for reasons that have nothing to do with parental responsibility, or the"
"Her question -- and mine: What message does the word "stepmother" convey more clearly than "You're NOT a mother"?"