from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A son of one's stepparent.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The son of one's stepfather or stepmother who is not the son of one's mother and is not the son of one's father.
- n. The stepson of one's father or mother which is not one's half-brother.
from the GNU version of the Collaborative International Dictionary of English
- n. A brother by the marriage of one's father with the mother of another, or of one's mother with the father of another.
from The Century Dictionary and Cyclopedia
- n. One's stepfather's or stepmother's son by a former marriage.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a brother who has only one parent in common with you
step- + brother (Wiktionary)