Definition of

Force

kicking a ball

Force is push or pull.

Unbalanced forces make an object accelerate.

The unit of force is the Newton (abbreviation is N).

A Newton is the force it takes to make 1 kg change its velocity by 1 m/s (meter per second) every second.

Which can be written:
1 N = 1 kg m/s2 (kilogram meter per second squared)