expander

/ɪkˈspændər/
noun
  1. A device or tool used to enlarge something or make it wider.
    • He used a pipe expander to widen the metal tube for the plumbing repair.
    • The orthodontist fitted her with a palate expander to correct her bite.
    • The shoe expander stretched the leather boots so they fit more comfortably.
  2. A substance or ingredient added to a product to increase its volume or bulk.
    • Some cheap sausages contain cereal expanders to make them appear larger.
    • Bakers sometimes use an expander in dough to create a lighter texture.
    • The manufacturer added a foam expander to the paint to increase coverage.
  3. A person or thing that causes growth or extension of something.
    • This software is a memory expander, allowing your computer to run more programs at once.
    • The grant acted as an expander for the research program, funding several new projects.
    • The new manager was a true business expander, doubling the company's revenue in one year.