Attire refers to a particular style of clothing. It is not a style such as a trend, but a style of clothing in relation to the type of occasion a person may be celebrating, or the type of environment in which an individual may be going. Appropriate attire for a black tie wedding, for example, could be a long black gown for a woman and a tuxedo for a man. For a white tie affair, it would be appropriate for a man to wear a white tie, vest, and shirt.
Business attire can vary widely depending upon the field in which one works. The finance and legal fields are known to be pretty conservative, so the attire of a banker, investment analyst, attorney, etc. is traditionally conservative with dark colored suits or dresses, etc. In less conservative fields such as the arts, virtually anything can go, so to speak. Examples are provided below.
Style lingo can be used such as,
“Business casual attire for event”
“Swimming attire for pool party”
“Casual attire for BBQ”
This gives the guests a sense of what the expect and how to dress up for particular events.