My friend Jerry, a scientist who studies Lake Erie algae, visited the GED class where I tutor to talk about his work. I learned a lot about his research, and I also learned some new words, which I’ve had fun investigating.
Jerry studies diatoms, one-celled plants that have a silica shell called a frustule. I rushed home to check out this word’s etymology and was gratified to find an interesting history. A frustum is a little bite or piece of something, both in English and in Latin, and the -ule ending (Latin frustulum), called a diminutive, makes it even littler and cuter. The frustules of diatoms are so cute and so little, you need a microscope to see them, and, fortunately, Jerry brought one today to allow us to gaze upon them.
Looking further, I discovered that the root of these words is the verb fruor, which means enjoy, as you would enjoy a little bite of food.
So frustule is related to the words fruit, fructose, and frugal, all derived from the verb fruor. (But not frustrate, from frustra, meaning in vain.)
Then I got curious about diatom and found it means cut in two, because diatoms appear to be in two parts. Each one has two thecae, or coverings. So a theca (and I’m going to share this first-declension singular and plural with my students tomorrow — theca and thecae) is a shield or container in Latin, borrowed from the original Greek word. Hence the words bibliotheca or bibliotheque for a library (holder of books) but also — wait for it — cinematheque (holder of movies!)
As my husband John, director of the Cleveland Institute of Art Cinematheque, points out, everything in the end comes back to the Cinematheque.