ses·ter·tium 
(sĕ-stûrshəm, -shē-əm)
(sĕ-stûrshəm, -shē-əm)n. pl. ses·ter·tia (-shə, -shē-ə)
A unit of currency in ancient Rome equivalent to 1,000 sesterces.
[Latin (mīlle) sēstertium, (a thousand) sesterces, genitive pl. of sēstertius, sesterce; see SESTERCE.]