1.  fluidounce(n = noun.quantity) fluid ounce - a British imperial unit of capacity or volume (liquid or dry) equal to 8 fluid drams or 28.416 cubic centimeters (1.734 cubic inches);
is a kind of british capacity unit, imperial capacity unit
is a part of gill
has parts: drachm, fluid drachm, fluid dram, fluidram

2.  fluidounce(n = noun.quantity) fluid ounce - a United States unit of capacity or volume equal to 1.804 cubic inches;
is a kind of united states liquid unit
is a part of gill
has parts: drachm, fluid drachm, fluid dram, fluidram

   See Fluid ounce, under Fluid. [1913 Webster]

fluidounce, n. US a fluid ounce (see OUNCE(1)).