(covers information from several alternate timelines)
Soh-chim is a Klingon word which has no direct translation, but is most closely approximated by "step-sister/brother" and similar to the Human concept of a "god-parent". A Klingon parent will bestow this title upon a respected adult friend. If accepted, the Soh-chim would be responsible for their child's future well-being in the event that the parent(s) could no longer do so; usually when the child's parent(s) go into battle and the odds are against returning. This agreement is legally binding and is well-recognized in Klingon law. The Soh-chim is usually someone who is a close family friend and already familiar with the child in question.