What do you mean by starch?

The word "starch" is taken from the Germanic root word meaning "strong, stiff, strengthen”.

It is an odourless, tasteless white substance that is manufactured in the green leaves of plants, from excess glucose produced during photosynthesis, and acts as a reserve food supply. 

It is stored in the chloroplasts in the form of minute granules in the seeds, tubers, and other parts of plants, and forming an important constituent of rice, corn, wheat, beans, potatoes, and many other vegetable foods.

It is the most common carbohydrate in human diets which is contained in large amounts in staple foods.