"Gain ground on somebody / something" or "Gather ground"?
I know the 1st expression, but I came across the expression "gather ground". According to my dictionary, it seems that "gather ground" has the same meaning as "gain ground", but I can't find the expression anywhere. I don't know if this is any kind of archaic expression or not. I don't even know the preposition used. Maybe "gather ground on somebody / something", I don't know.
Thank you in advance!