That’s not the end of the story of course. Testum is related to another Latin word, testa (like a piece of clay), as well as texere, to weave. Texere happens to be the root of the Latin word textura, which might look familiar because it means texture. Makes sense, right? Weave, textile, texture.
Next, we’re going to look at the word text. It showed up in the late fourteenth century as the words on a page (I’m guessing you all know that the texting we do with our phones came much later ; ). It has its origins in the Old French texteand Old North French tixte, but as always it comes back to Latin, in this case the word textus. Now, textus has a few different meanings depending on which version of Latin you look at. In Medieval Latin it can refer to the Scripture or the just plain text of a book. Late Latin uses it similarly to the latter definition, with it being a written account or the content of a document. Both those versions come from classical Latin, where it means texture. The reason I bring up all this? It comes from texere.
Tester as we think of it didn’t come around until the seventeenth century, about seventy years after the new definition of test did. Before that there was tester, but it was a canopy over a bed. That obscure definition comes from the Medieval Latin testerium and testera—“head stall”, and Late Latin slang for skull, testa. Since this tester is obsolete, this might not seem important, but it’s funny because the word testy can also be traced to the Late Latin testa. So rather than the route you might think, it came about because of a word none of us use anymore. It’s not related to any part of the male anatomy. Unlike, say, the word testament.
Dr. Rebecca R. Harrison’s page at Truman State University