IPA: /ˈstɛpˌbrʌðər/
KK: /ˈstɛpˌbrʌðər/
A male child of one's step-parent, who is not a biological sibling.
My stepbrother and I enjoy playing video games together.
Stepbrother → The word is formed from "step-" (from Old English "stæpe", meaning a step or degree of relationship) and "brother" (from Old English "brōþor", meaning a male sibling). A stepbrother is a male sibling who is related by marriage rather than by blood, indicating a step or degree of relationship.
Think of 'step' as a degree of relationship, showing that a stepbrother is a brother through marriage, not blood.