STEPBROTHER
stepbrother, half-brother, half brother
(noun) a brother who has only one parent in common with you
Source: WordNet® 3.1
Etymology
Noun
stepbrother (plural stepbrothers)
The son of one's stepparent who is not the son of either of one's biological parents.
The stepson of one's parent who is not one's half-brother.
Synonyms
• stepbro
Hypernyms
• stepfamily
stepsibling
stepson
Source: Wiktionary
Step"broth`er, n.
Definition: A brother by the marriage of one's father with the mother of
another, or of one's mother with the father of another.
Source: Webster’s Unabridged Dictionary 1913 Edition