» The term semi-formal's also used in formal methods (computer science) to mean not fully semantically formalized. In Western clothing, Semi-formal's a grouping of dress codes, indicating the sort of clothes worn to events with a level of formality between informal (for example lounge suit) and formal. Historically there were both day and evening semi-formal dress codes, but this category's now seen almost exclusively in the context of evening wear. Background The origins of semi-formal attire… (More on Semi-formal)