My mother has a boyfriend, he has kids. How do I refer to them in relation to me besides saying my mom's boyfriend's kids. My mother is not biologically related to her boyfriends kids.


2 Answers 2


There's the term "prospective step-siblings", which implies a significant possibility that the parents will get married. You could also precede "step-siblings" with a variety of modifiers, such as "quasi", "pseudo", "para", "almost", etc. You could also apply modifiers directly to "siblings", either the above, or another such as "meta", "allo", etc.


A version of the popular phrase, "My brother from another mother" comes to mind. How about "My brother from my mother's significant other? or the shorter "Siblings from mom's (or dad's) Significant Other."

  • Why not simply say what the OP said: "My brother from my mother's boyfriend"? The only advantage provided "significant other" would be if my mother's boyfriend is something other than a boyfriend, e.g., a girlfriend. Sep 1, 2016 at 5:22
  • 1
    if someone was talking to me about their 'brother from their mother's boyfriend' I think I would assume that they meant the two of them shared a mother but not a father.
    – Spagirl
    Sep 1, 2016 at 12:56

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