Black's Law Dictionary (2nd edition)dictionaries

Unio Frolium

Lat. Uniting of off-spring. A method of adoptlon, chiefly nsed in Germany, by which step-children (on ei-ther or both sides of the house) are made equal, in respect to the right of succession, with the children who spring from the mar-riage of the two contracting parties. See Heinecc. Elem. | 188

Source: Black’s Law Dictionary 2nd Ed (1910)