I'd research the terms and stuff . . . if it was important for the story. Since their clothing generally doesn't help advance the plot or character much, it doesn't really get mentioned except in general terms.

THIS dress however was supposed to exude arrogant power, so I spent a minute or two in the book trying to make it exude that by mentioning a few unique items of the dress. This is apparently what caused the problems. I couldn't use the correct terms even then, because the book is in the first person and this person wouldn't have any idea what the correct terms would be, but still . . .