We all know how crucial accuracy is when it comes to any historical drama. Whether this drama comes from a book or movie, accuracy is key to feeling immersed in the period selected by the medium. Writing in historical fiction or fantasy requires a lot of detail when it comes to world-building. This detail can range from what technology is available to your characters to what diseases affect the general population. Somewhere in that range, the type of clothing your characters wear will factor in. Researching the fashion of an era can get complicated when it comes to using the right vocabulary. Using the right vocabulary can get even more complicated the further back in time you go, which usually results in "tunic" becoming your primary label.
The proper research to curate a helpful vocabulary list can make world building easier. Below I've listed several different sites I've come across during my internet browsing. Each of these sites a great for providing period-friendly terminology depending on the era.
This website offers both a dictionary and sections of history ranging from "the ancient world" to the 21st century.
This site has links throughout the page that ranges (but is not limited to) the Regency era to the 1990's.
Of the sites on this list, this one will have the least amount to offer from it's home page. This page does however provide many more links to blogs, other websites and research the blogger has curated on her own.
This blog offers a very interesting timeline with history behind the evolution of fashion from era to era.
As the title implies, this glossary list is focused entirely on the Medieval era. It's a perfect way to avoid overusing "tunic" all the time.