any unit used in linear measurement, as the inch, foot, meter, etc. Origin of linear measure. 1885-1890. First recorded in 1885-90.
Realistically, you could put any icing you wanted on a carrot cake. The wonderful beauty of cooking is that you can make it to your liking. But, the traditional icing that most people put on carrot cake is cream cheese icing.
However, if the cake has icing, it depends on the type of icing whether the cake should be refrigerated or allowed to sit at room temperature. Icing made with butter, whipped cream, or cream cheese (for example, our Carrot-Apple Spice Cake with Browned Butter Glaze) should be covered and refrigerated.