A chinois is a conical sieve with an extremely fine mesh. It is used to strain custards, purees, soups, and sauces, producing a very smooth texture. It can also be used to dust food with a fine layer of powdered ingredient.
A related utensil is the Tamis – a flat strainer through which food is pressed with a scraper or pestle.
A similarly-shaped utensil is the China cap, a reference to the conical Asian hats common in China. It is a perforated metal conical strainer with much larger holes than a chinois. A China cap is used to remove seeds and other coarse matter from soft foods, but produces a coarser-textured product than the chinois.
Both the chinois and the China cap often are used with a cone-shaped pestle. With the pestle tip placed in the bottom of the strainer, it is rolled against the sides of the device to work liquids and soft food through it. In this way, the chinois functions much like a tamis, and the China cap functions similar to a food mill.