Glossary of Terms
 
  cans  
  An informal term for headphones — devices that can be worn on the head with small speakers that fit over the ears (or sometimes into the ears). The connector commonly used for headphones is a 1/4-inch stereo plug, also known as TRS (tip/ring/sleeve). Inexpensive models of headphones often use an 1/8-inch stereo plug.  
  Source: Yamaha  

Related terms:
  1/4-inch jack   1/4-inch plug   1/8-inch jack   1/8-inch plug   TRS