Unlearn something false every day

[womzilla]

Many and many a year ago--much more than half my life hence--I learned that "testimony" comes from the same word as "testicle", and was related to the classical Roman practice of swearing with one's hand on one's genitals.

A few days ago, someone quite learned on my friendslist made a similar comment except attributing the practice to the ancient Hebrews. With an audible clang, all of my pseudoxia detectors kicked in. Two minutes googling found this in a comment to a post on LanguageHat, discussing how the words "capon" and "head" are related.

The etymological association between testis, witness, and testicle is cute, but very controversial. Here's Mr. OED on the anatomical testis:

[L.: etymology uncertain.
An assumed identity with testis witness (quasi 'the witness or evidence of virility') is rejected by Walde, who suggests connexion with testa, pot, shell, etc. In 16th c. Fr., however, tesmoing 'witness' appears in this sense: see Godef.s.v.]

I could readily a believe a popular association between witnessing and the ballocks, but the sense development of testis (pot) to testis (head) makes sense of the transition from pot to gonad. The AHD, on the other hand, offers:

Another theory says that the sense of testicle in Latin testis is due to a calque, or loan translation, from Greek. The Greek noun parastates means "defender (in law), supporter" (para– "by, alongside," as in paramilitary, and –states from histanai, "to stand"). In the dual number, used in many languages for naturally occurring, contrasting, or complementary pairs such as hands, eyes, and ears, parastats had the technical medical sense "testicles," that is, "two glands side by side." The Romans simply took this sense of parastates and added it to testis, the Latin word for legal supporter, witness.

Which I like, actually--compare "epididymes," i.e., twins.

(Formatting cleaned up.)

Ah, well. My mind is better for this bit of unlearning. As folk etymologies go, it was one of my favorites.