Related Clues:

• Part of 'E = mc2'
• Lack of movement
• Physics 101 topic
• Fathers celebrate it?
• Sunday celebration
• Newton subject
• Communion service
• Body measurement
• It's said on Sundays
• Subject of Newton's first law of motion
• Sunday event
• Catholic communion
• Immobility
• Part of the relativity equation
• Considerable number