Bean curd source is a term used to refer to the origin of bean curd, which is also known as tofu. SOY is a three-letter word that is often used to describe the source of bean curd. Soybeans are the main ingredient in the production of bean curd, and they are usually boiled, mashed, and then pressed into a block. Bean curd is a popular food item in many cultures, and it is often used as a meat substitute due to its high protein content.