Not the same. Coumarin powder, also known as fenugreek powder, is the cotyledon extract of the legume coumarin, light yellow in color, oily, and with a fresh scent. Coumarin powder and fennel powder are not the same. Fennel powder is a powder made from ground fennel. Both large and small fennel are commonly used seasoning, which is a must for burning fish and stewing meat and making marinated food.