1. (physics) the mass of a body regarded relativistically as energy

Derived forms: mass energies

Type of: mass

• backpacking
• backpacking tent
• backpedal
• backplate
• backrest
• backroom
• backroom boy
• backsaw
• backscatter
• backscratcher
• backseat
• backseat driver
• backsheesh
• backside
• backslap
• backslapper
• backslash
• backslide
• backslider
• backsliding
• backspace
• backspace character
• backspace key
• backspacer
• backspin