Electric field strength	Gravitational field strength
The is strength of an electric field is a measure of the force that would be exerted on a body in the field of unit positice charge.	The is strength of a gravitational field is a measure of the force that would be exerted on a body in the field of unit mass.
E = F / Q	g = F / m

Notes:

• Field strength as mass per unit charge / mass is clearly a vector quantity.
• The above definitions are theoretical, If unit mass / charge where brought into a field then they would affect the field strength. Inorder to get a value that is closest to correct, we use a mass or charge that is comparitivly tiny to that whose field we are measuring.
• As there is only positive mass, there are only positive gravity fields, and whereas over a distance, electric fields tend to cancel each other out, gravity fields get far more important.
• Intensity is just another word for field strength