A sachet is a small disposable bag, often used to contain single-use quantities of consumer goods, such as ketchup or shampoo.
Pronouned "sash-ey"
A sachet can also be a fabric bag containing pot pourri.
Sale of products, such as shampoo and detergents, in sachets is very popular in India and other Eastern countries.
In culinary terms, a sachet is a small bag made of cheesecloth, containing various herbs and spices (typically bay leaf, thyme, parsley stems, and black peppercorns) used to infuse flavor into stocks.