If person A is the sister-in-law of person B, then in common usage, person A could be person B’s: Don’t assume which relationship it is and don’t assume that the “in-law” is in in-law through the current marriage. It could have been from a former one–particularly if that marriage ended due to the death of a previous spouses. In some families, the use of the term “in-law” will continue even if marriage ended in divorce. This 1950-era newspaper clipping indicated that Mrs. Mundy and Mrs. Wetzel are sisters-in-law. Mrs. Wetzel’s first husband, Herman Trautvetter, was a brother to Mrs. Mundy.
Get the Genealogy Tip of the Day Book