Real Dictionary

starch
a polysaccharide composed of glucose units that occurs widely in plant tissues in the form of storage granules, consisting of amylose and amylopectin [...]
variable noun: Starch is a substance that is found in foods such as bread, potatoes, pasta, and rice and gives you energy.

starch in American English
a white, tasteless, odorless food substance found in potatoes, rice, corn, wheat, cassava, and many other vegetable foods: it is a granular solid, chemically a complex carbohydrate, (C6H10O5)n, and is used in adhesives, sizes, foods, cosmetics, medicine,
to stiffen with or as if with starch
noun: a white, tasteless, solid carbohydrate, (C6H10O5)n, occurring 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
transitive verb: to stiffen or treat with starch

starch in British English
adjective: (of a person) formal; stiff
noun: a polysaccharide composed of glucose units that occurs widely in plant tissues in the form of storage granules, consisting of amylose and amylopectin
verb: to stiffen with or soak in starch

starch in the Pharmaceutical Industry
Starch is a polysaccharide used as a dusting powder, and as a disintegrant, filler, and binder in pharmaceutical preparations.