1.nounA little roll; a roll of coins put up in paper, or something resembling such a roll.
2.nounA decorative technique that involves creating patterns with piping, cording or bias tape. A rouleau loop uses the same cord or piping as a way of fastening buttons, most notably down the back of bridal gowns.
"rouleau loop"
3.noun(chiefly in the plural) A stack of aggregated red blood cells, as seen in certain haematological and other diseases.
4.noun(fortification) One of a bundle of fascines to cover besiegers.