/ses"terrs/ , n.
a silver coin of ancient Rome, the quarter of a denarius, equal to 2 1 / 2 asses: introduced in the 3rd century B.C.
[ 1590-1600; sestertius, equiv. to ses- half-unit (see SESQUI-) + tertius THIRD (i.e., 2 units and half a 3rd one equal 2 1 / 2 asses) ]