Words I Learned From Reading David Foster Wallace

animalculum (n.) – microscopic organism such as an amoeba or paramecium

“Nor does he give any examples to help explain irregular participles and transitivity (“The light shone” vs. “I shined the light,” etc.), and these would seem to be more important than, say, the correct spelling of huzzah or the plural of animalculum, both of which get discussed.”

Wallace, David Foster. “Authority and American Usage.” Consider the Lobster. New York: Back Bay Books, 2007. p 118.