[Coda]

Uniform means it doesn't vary. The strength is the same everywhere. It doesn't follow the inverse square law because it says it doesn't. :P (In the real world, a uniform field is an approximation of the field between two oppositely-charged flat plates held at a fixed distance from each other.)

The magnitude (sometimes called "strength" or "intensity") of an electric field is, as I said, force / charge. It measures how much force the field can exert per unit charge.