Collar color is a set of terms denoting groups of working individuals based on the colors of their collars worn at work. These commonly reflect one's occupation within a broad class, or sometimes gender. White-collar workers are named for the white-collared shirts that were fashionable among office workers in the early and mid-20th century. Blue-collar workers are referred to as such because in the early 20th century, they usually wore sturdy, inexpensive clothing that did not show dirt easily, such as blue denim or cambric shirts. In the modern era, these terms have become metaphorical and are not a description of typical apparel.