Credit goes to the great Ian Fleming for this Spectacular Vernacular.

My opuscula do not aim at changing people or making them go out and do something.

Ian Fleming, “How to Write a Thriller,” Books and Bookmen, May 1963 (Reprinted in Literary Hub, May 28, 2019)

Opuscula is the plural form of opusculum because we like to make the English language as difficult as possible to learn.

Opus is Latin for work or labor. Music fans will recognize both the modern use of opus, for a musical composition, and its plural, opera. Yes, once again, we make plurals difficult.

Since culum is a diminutive suffix, opusculum translates as little opus and has come to refer to a minor literary work.

Thus, Mr. Fleming was referring to his writings as minor works, though his character of James Bond is known around the world as is his children’s book, Chitty Chitty Bang Bang: The Magical Car.