(grammar) A noun that denotes an agent that performs the action denoted by the verb from which the noun is derived, such as "rider" derived from "to ride", or "cutter" derived from "to cut".

Any substance that will produce a foam under specified conditions

any substance used to increase viscosity, especially of a food product

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 potent herbicide and defoliant used by US forces in the Vietnam War.

A substance, such as a surfactant, that reduces the surface tension of a liquid, allowing it to spread across and penetrate the surface of a solid.

(chemistry) Any substance that reduces, or donates electrons to, another; in so doing, it becomes oxidized.

(chemistry) Any substance that oxidizes, or receives electrons from, another; in so doing, it becomes reduced.

A person who finds jobs for actors, models, and other people in the entertainment business.