A relationship resulting from a remarriage.
[Old English stēop-, from a Germanic base meaning bereaved, or orphaned.]
Terms in step- refer to a person in a family relationship but unrelated biologically. Originally it referred only to relationships resulting from remarriage after the death of a spouse; in the nineteenth century terms were extended to refer to any relationship resulting from remarriage, say following divorce. Examples include stepmother and stepfather (together, stepparent) stepbrother and stepsister (together, stepsibling), stepson and stepdaughter (together, stepchild) and stepfamily.