Lewis & Short

Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.

sŏcer (nom. socerus, Plaut. Cas. 4, 2, 18; id. Men. 5, 5, 54; with socer, id. ib. 5, 7, 56), ĕri, m. [Gr. ἑκυρός].

  1. I. A father-in-law, Plaut. Stich. 4, 1, 22; id. Trin. 5, 2, 27; Cic. Off. 1, 35, 129; id. Lael. 1, 1 and 5; Caes. B. G. 1, 12 fin.; Ov. M. 1, 145; Hor. C. 3, 11, 39; id. Ep. 1, 19, 30 al.; v. also socrus.
    Plur. soceri, parents-in-law, Verg. A. 2, 457; 10, 79; Ov. M. 3, 132.
  2. II. Transf., for consocer, a son’s father-in-law, Ter. Hec. 5, 2, 4: magnus, grandfather-in-law, i. e. one’s husband’s or wife’s grandfather, Dig. 38, 10, 4, § 6; called simply socer, ib. 50, 16, 146; cf. ib. 3, 1, 3; 23, 2, 14 fin.: socer major, a great-grandfather-in-law, Paul. Diac. p. 136, 10.

socrus, ūs (orig. comm.; v. infra), f. [a collat. form of socer; Gr.ἑκυρός], orig.also m., either a father-in-law or a mother-in-law; but of the first signif. we have only two examples in ancient poets: praemia erepta a socru suo, Att. ap. Prisc. p. 698 P. (Trag. Rel. p. 136 Rib.); and: a socru, Oenomao rege, Poët. ap. Cic. Tusc. 3, 12, 26 (Rib. l. l. p. 213).
The signif. mother-in-law was the prevailing one through all periods of the language: uno animo omnes socrus oderunt nurus, Ter. Hec. 2, 1, 4; 5, 1, 22; cf. Ov. F. 2, 626; Ter. Hec. 2, 3, 4; 4, 4, 83; Cic. Clu. 12, 23; Juv. 6, 231; Dig. 23, 2, 14, § 4.
Collat. form SOCERA, ae (acc. to socer), Inscr. Orell. 289; and contr. SOCRA, ib. 4221: magna, grandmother-in-law, i. e. one’s husband’s or wife’s grandmother: major, the great-grandmother of either party, Dig. 38, 10, 4, § 6; Fest. p. 126 Müll.