A plant root resembling ginger, but smaller. Used for its yellow color and pungent taste. To use, peel and grind  it in a pestle with other spices. Hard to find fresh but widely available in powdered form.

Culinary Uses
Turmeric is often used to replace saffron, a much more costly spice. It is added to food to color it yellow, particularly rice and broths, but it does not have the taste of saffron. Saffron should always be purchased in threads or strands, since if you purchase it powdered, you may actually be buying an alarming percentage of turmeric!

Gourmetpedia

India
In India it is possible to buy a piece of turmeric (baldi) that can be added to color a dish at any point during its cooking time.

Colombo Powder and Mild Ceylon Curry
Some people think that West Indian “colombo” and Indian masala are similar, but even if the Sinhalese brought this spice blend to the West Indies in the nineteenth century, the original recipe seems to have been sunk somewhere over the Atlantic! The only remaining link is the name Colombo, the capital of Sri Lanka.

In the West Indies, the spice mixture is used to flavor the national dish of goat, pork or chicken colombo.