I realize that there are sites with the names and uses of various articles of clothing but I think for those less familar with them this might be a good place for a dictionary of clothing terms and if applicable to only a short time period what that is. I bow to those with greater experience to start this list.
{moderator} Most Excellent... Agreed. Remember to KIS (Keep it simple) Folks! Thank you! {/moderator}
OK: Partlet (also referred to as coverciere, coletti, reti, net, gorgiere )
A nice little cloth to cover up the decolletage. As far as I remember it came into fashion because dresses were at one point (in the 15.th century) so exposing that a law was made about how much cleavage one could show. The clever Florentine ladies responded with using the finest, most transparent silk ever made in the neck opening, while still exposing their cleavage to the world... ;D :D There is an own chapter about it in "Moda a Firenze" (page 119-127), for those who's interested.
The partlets started out as quite unornamented, transparent "shawls", but developed into heavily decorated objects which eventually ended up as the heavy ruff of the late 16.th/early 17.th century. The picture gallery underneath shows Florentine fashion, but it also shows a general trend that appeared in other cities and countries.
http://img.photobucket.com/albums/v31/operafantomet/renaissanceportraits/firenze1/ginevradebenci.jpg
Aye, she IS wearing a partlet....
http://img.photobucket.com/albums/v31/operafantomet/renaissanceportraits/firenze2/bronzino1540.jpg
Quite ornamented, but very similar shape to the Ginevra portrait. (Slightly off-topic: Anyone familiar with this "wavy metal thread" technique? It also appears in the hairnet of Raphael's "Donna Gravida" and the partlet of Bronzino's "Lucrezia Panciatichi". "moda a Firence" claims it to be merely starched linen, but it looks to me like metal threads are involved as well?).
http://img.photobucket.com/albums/v31/operafantomet/renaissanceportraits/firenze2/bronzino1543.jpg
A beginning collar, and even more ornamented.
http://img.photobucket.com/albums/v31/operafantomet/renaissanceportraits/firenze3/allori1557.jpg
The decorations can remind of Eleonora di Toledo's partlets, but this one has the emphasis on the standing collar.
http://img.photobucket.com/albums/v31/operafantomet/renaissanceportraits/firenze3/allori1575.jpg
Mostly collar, very little partlet. This is also due to the neckline of the outer garb becoming V shaped rather than square. The way from this and to the first closed ruffs aren't long (though ruffs are also related to the shirt/chemise collars).
ETA: Some partlets, especially the early Florentine ones, are on top of the dress and barely covers the shoulders, like the one in Raphael's Maddalena Doni portrait:
http://img.photobucket.com/albums/v31/operafantomet/renaissanceportraits/firenze1/raphael1506.jpg
Others seems to go under the dress; Jennifer Thompson has reconstructed one that is like a small "waistcoat", with armholes and a collar. If I could only find a photo of it....
I found a wonderful dictionary resource: http://www.renaissancemagazine.com/glossary/
I pasted some of the definitions here.
FARTHINGALE: The canvas or linen petticoat containing whalebone hoops worn in the 16th century.
FRENCH HOOD (1530-1630): A small bonnet made on a stiff frame and worn far back on the head. Folds of material fell below the shoulders from a short flat panel at the back. They were usually dark in color but decorated with "biliments" (borders of silk, satin, or velvet, and trimmed with gold or jewels) and worn over a crespin.
FOREPART: Any underskirt-usually highly decorated-which was revealed through the inverted-V opening in the front of a skirt.
DOUBLET: A masculine tunic worn especially from the 15th to 17th century. Originally of quilted manufacture, although its style changed over the years, it remained a fundamental outer body garment.
BODICE: 1. The close fitting upper part of a woman's dress. 2. A woman's wide, sleeveless vest tightly laced in front, worn over a blouse or dress, usually low-cut.