What exactly is weakly informative prior?

Is there a precise definition of weakly informative prior?

How is it different from a subjective prior with broad support?

• My understanding is that a weakly-informative prior expresses more about the researcher's attitude towards the prior, rather than any mathematical properties of the prior itself. The canonical example would be Gelman's recommendation of a Cauchy prior with location 0 and scale 5/2 for logistic regression. – Sycorax Oct 22 '13 at 16:24