From Nancy Friedman, a link to this cartoon by Scott Hillburn:
Oh, not a conjugal visit, a conjugational visit! Let’s conjugate, baby!
The Latin verb conjugāre ‘to yoke together’ (con- ‘together’ plus jugāre ‘to join, yoke, marry’) lies behind both words. Conjugate came to English as a technical term from Latin grammar, meaning ‘to inflect (a verb)’ (OED2’s first cite is 1530), though there are some later (rare) cites for the verb in the sense ‘yoke together, couple; join together, unite’ (but apparently not used for sexual union).
Conjugal ‘of or pertaining to marriage, matrimonial’ is also 16th century. Historically, sexual union was one of the central features of marriage (right up there with property rights), so that the specialization of conjugal to sexual matters in some contexts isn’t surprising. Conjugal visit (of the prison variety, as in the cartoon) isn’t in OED2, but will surely be added soon in the on-going revisions of the dictionary. (Surprisingly, it isn’t in NOAD2 or AHD4, either, though it’s a commonly used expression whose meaning certainly can’t be predicted by general principles from the meanings of its parts. Conjugal in this expression is an excellent example of a non-predicating modifier.)
[Bonus: on the Wikipedia page (which has information on conjugal visitation in a number of countries), we learn that
In June 2007, the California Department of Corrections announced it would allow same-sex conjugal visits. The policy was enacted to comply with a 2005 state law requiring state agencies to give the same rights to domestic partners that heterosexual couples receive. The new rules allow for visits only by registered domestic partners who are not themselves incarcerated. Further, the domestic partnership must have been established before the prisoner was incarcerated.
(Slowly, things change.)]
