“mite,” “scab,” “tick” — zoological/parasitological combining form
The word entered English in the 1840s as acarid (noun), borrowed from Modern Latin acarus, from Greek ἀκάρι (akari) — literally “mite” (originally denoting the specific mite causing scabies). The noun acarocele appeared in the 1900s. The root akari (“mite”) connects acar- to the entire parasite and arthropod roots: acaricide (acar- + -cide → agent that kills mites), acarophobia (acar- + phobos → fear of mites or ticks), and acarology (acar- + logos → study of mites). The combining formacar- is productive in parasitology, dermatology, and entomology: e.g., acaroid, acaricidal, acaricide, and Dermanyssus.