1. Acting as or providing a complement (something that completes the whole)
   - complementary, completing

See also: additive, complement

• backspace
• backspace character
• backspace key
• backspacer
• backspin
• backstabber
• backstage
• backstair
• backstairs
• backstay
• backstitch
• backstop
• backstory
• backstroke
• backstroker
• backswept
• backswimmer
• backswing
• backsword
• backtalk
• backtrack
• backup
• backup man
• backward
• backward and forward