twofer

noun4

1. •
   [before a noun] Something sold at a discount of two for the price of one.

   • I dashed into the mall; bought a gift; raced to the card store, snapped up a two-fer gift-bag special and was back in my car in 26 minutes. I could medal in power shopping. — 2004
2. •
   Something that yields a substantial additional benefit; something that figuratively kills two birds with one stone.

   • Justice Clarence Thomas served up a twofer last week […] — 2021
3. •
   A cabling device used in theatre, allowing two stage lighting instruments to be connected to one dimmer.
4. •
   The fashion of wearing long sleeves outside a short-sleeved shirt.