In the European tradition, casual is the dress code that emphasizes comfort and personal expression over presentation, formality and conformity. More simply, "casual" can be defined as something relaxed, occasional, not planned, or informal. It includes a very wide variety of costume, so it is perhaps better defined by what it is not than what it is. The following are not considered casual wear: Basic materials used for casual wear include denim, cotton, jersey, polyester, flannel, and fleece. It is best to avoid wearing materials such as velvet, chiffon, and brocade.