Conceit is the name given to a common rhetorical device. In it, two things that are extremely different are compared through the use of similes and metaphors. These comparisons tend to be clever, and unexpected. In the poem "She Walks in Beauty," Byron compares a woman's beauty with natural elements of a dark quality, such as the "night" and a "starry sky." This is particularly unusual when we consider that the woman is described as pure and sweet, things that are usually not considered dark.