Definition of arbacia
1 capitalized : a genus of sea urchins (order Centrechinoida) having the ambulacral plates with three pairs of pores, the periproct covered by four triangular plates, the test rather low and stout, and the spines short with those near the mouth having enameled flattened tips
2 plural -s : a sea urchin of the genus Arbacia
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Origin and Etymology of arbacia
borrowed from New Latin, perhaps from Arbaces, legendary ninth century b.c. Median general (borrowed from Greek Arbákēs) + -ia -ia
First Known Use: before 12th century
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