newton Syllabification: (new·ton)Pronunciation: /ˈn(y)o͞otn/ (abbreviation: N)Definition of newton noun Physics the SI unit of force. It is equal to the force that would give a mass of one kilogram an acceleration of one meter per second per second, and is equivalent to 100,000 dynes. Origin: early 20th century: named after Newton, Sir Isaacnewton in other Oxford dictionaries Definition of newton in the British & World English dictionary