decurion

[dih-kyoo r-ee-uh n] /dɪˈkyʊər i ən/
noun, Roman History
1.
the head of a decury.
2.
a member of the senate of an ancient Roman colony or municipality.
Origin
1350-1400; Middle English < Latin decuriōn- (stem of decuriō), equivalent to decuri(a) a division of ten (dec(em) ten + -uria -ure) + -iōn- -ion
British Dictionary definitions for decurion

decurion

/dɪˈkjʊərɪən/
noun (in the Roman Empire)
1.
a local councillor
2.
the commander of a troop of ten cavalrymen
Word Origin
C14: from Latin decuriō, from decuria company of ten, from decem ten