Definition of "adrogation"

There were certain sacred rites (sacra gentilitia) which belonged to a gens, to the observance of which all the members of a gens, as such, were bound, whether they were members by birth, adoption, or adrogation. A person was freed from the observance of such sacra, and lost the privileges connected with his gentile rites, when he lost his gens, that is, when he was adrogated, adopted, or even emancipated; for adrogation, adoption, and emancipation were accompanied by a diminutio capitis.

1848, G[eorge] L[ong], “GENS”, in William Smith, editor, Dictionary of Greek and Roman Antiquities, 2nd improved and enlarged edition, London: Taylor, Walton, and Maberly, Upper Gower Street; and Ivy Lane, Paternoster Row; John Murray, Albemarle Street, page 568, column 2