What is the difference between glace and butter icing?Can you guys answer in English?Thanks a lot

Well,first off,the term glace comes from the French Glacé,which used in reference to a sauce means icing or glaze.Glace by all means to make the object to have a smoothier and glossier surface.You can use sauce to glace your poultry,use syrup or honey to glace the walnut,apple,and doughnut.You could glace them all.
Yet,for Butter icing,or butter cream,is a sweet mixture most often used to fill and decorate cakes including sandwich cakes,layer cakes and cupcakes if that's what you are looking for.But it also depends on the kind of sugar and cream you use the color and texture could be different.ehhh,what do i know anyway...