Dried, ground turmeric is a yellow powder that can vary widely from deep yellow-orange to bright yellow. Turmeric is typically used in curries and is a major component of curry powder. It is suitable for gluten-free, vegan, vegetarian, and paleo diets.
 
The yellow colour in many Indian, Thai, and Asian dishes and spice blends is often a result of turmeric. Known as "Indian saffron"  due it being native to India and imparts the same colour as saffron. In addition to being used across Asia, it is also found in Middle Eastern cooking. 
 
Turmeric is a light orange-yellow, fine powder with earthy, pungent and bitter flavour.  
Part of the reason that turmeric is in curry powder is that it adds an element of deliciousness to food.