Turmeric is a bright yellow-orange powder used in cooking. It is made from the dried, ground root of a plant related to ginger — and in fact you can buy the fresh root too, which looks like a small orange ginger, though the powder is what most people mean. It is one of the main things that makes curry yellow. The taste is warm, slightly bitter and earthy, not hot; people who expect it to burn their mouth are surprised. Cooks also use it just for the colour, in rice, pickles and mustard. In the last fifteen years or so it has become a health-food word in English too: you will see "turmeric latte" or "golden milk" on café menus, and people take turmeric tablets because of a substance in it called curcumin, which some studies link to reducing swelling in the body. Be a little careful with that — the health claims you read online are usually much bigger than what the research actually shows. It is an uncountable noun, so: some turmeric, a teaspoon of turmeric, not "a turmeric" or "two turmerics". The one practical thing every cook learns the hard way: it stains. It will turn your fingers, your cloth and your plastic containers yellow, and the marks do not wash out easily.