from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The husband of one's mother and not one's natural father.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The husband of one's biological mother, other than one's biological father, especially following the divorce or death of the father.
from the GNU version of the Collaborative International Dictionary of English
- n. The husband of one's mother by a subsequent marriage.
from The Century Dictionary and Cyclopedia
- n. A man who is the husband of one's mother, but is not one's father.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the husband of your mother by a subsequent marriage
step- + father (Wiktionary)