ac·​a·​rus | \ ˈa-kə-rəs How to pronounce acarus (audio) \
plural acari\ ˈa-​kə-​ˌrī How to pronounce acarus (audio) \

Definition of acarus

: mite especially : one of a formerly extensive genus (Acarus)

First Known Use of acarus

1657, in the meaning defined above

History and Etymology for acarus

borrowed from New Latin, a re-formation as a masculine noun of Greek akarí (neuter) "mite," probably of pre-Greek substratal origin

Note: The masculine re-formation of Greek akarí is perhaps late Medieval Latin; the form appears in 16th-century Latin/vernacular dictionaries such as the Dutch-Latin dictionary of Cornelis Kiliaan. Greek akarí is conventionally associated with the adjective akarḗs, "tiny, minute," though of equal if not more relevance might be kárnos, "louse" (Hesychius) and kóris, "bedbug."

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The first known use of acarus was in 1657

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Cite this Entry

“Acarus.” Dictionary, Merriam-Webster, Accessed 17 Jan. 2021.

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More Definitions for acarus


ac·​a·​rus | \ ˈak-ə-rəs How to pronounce acarus (audio) \

Medical Definition of acarus

1 capitalized : a genus of arachnids including a number of small mites and formerly including all mites and ticks
2 plural acari\ -​ˌrī How to pronounce acarus (audio) , -​ˌrē How to pronounce acarus (audio) \ : mite especially : one of the genus Acarus or formerly included in this genus

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