Puce is a color traditionally described as dark purplish-brown, although this definition is changing over time. In the UK it is still fairly true to its original meaning, a sort of muddy plum color.1 In the USA it is fairly common to see a pink/purple pastel shade referred to as puce, presumably as a shortening of a shade that was previously called 'puce pink'2. It is also somewhat common, particularly in the United States, to find a color referred to as 'puce green'3, probably as a mispronunciation of 'puke green'. Puce green has become so common a term that you can buy puce green tattoo ink, but it is not generally recognized as a formal color.
Originally, puce was a dark purple-brown that was supposed to be the color of a flea (most likely, a flea that had just had a good meal of blood), and puce is in fact the French word for flea, which in turn comes from the Latin word for flea, pulex. It was first used in English in a book on fly making in 1787 (A Concise Treatise on the Art of Angling by Thomas Best). At this time is was already used as a color term in France, and was said to be quite popular with Marie Antoinette. Even so, it took nearly 40 years before it was regularly used for fabrics in England. It has since then passed from the world of fashion into general usage... more or less.
1. Puce (UK): Hex triplet #722F37; sRGBB r114, g47, b55; CMYKH c0, m59, y52, k55; HSV h353°, s59%, v4511%.
2. Puce Pink (US): Hex triplet #CC8899; sRGBB r206, g36, b10; CMYKH c0, m33, y25, k20; HSV h345°, s33%, v80%.
3. Puce Green (YMMV): Hex triplet # A58B34; sRGBB r165, g139, b52; CMYK c35, m39, y97, k8.