The substance that creates the buoyancy of a balloon or other airship; normally hydrogen, helium or hot air.

Any organism or substance added to a food product (such as dough or batter) that makes it rise when cooked.

A female agent provocateur; a woman who incites someone to do something, especially something incriminating.

A person who secretly disrupts a group's activities from within the group, particularly by encouraging or committing illegal acts to discredit the group or expose them to prosecution; an instigator, troublemaker.

a catalyst

Any noxious substance intended for use in military or police operations.

Any food additive added to react with pectin and give the food product a stronger structure.

any substance added to a food product to provide the texture of a gel

Any substance added to another product to prevent it from forming lumps.

any substance added to flour in order to improve some aspect of its performance