camp vs gank
Repetition. A gank is one surprise attack on a lane; camping is coming back to gank the same lane again and again, until its player cannot play anymore.
camp
Camping is picking one lane and staying on it: gank after gank, often because the player there is already behind, or because that lane is easy to surprise. The word also names the jungle monster groups, and context separates the two. "jgl camping top" is a top laner's complaint, and information for the other two lanes.
open the page →gank
The gank is the attack itself: the jungler arrives on a lane, catches the enemy two against one, and leaves. A gank is an event; you can do one per lane per pass. "gank mid", "care lvl 2 gank".
open the page →Why they get mixed up
A camp is made of ganks, hence the mix-up. The difference matters to whoever suffers it and to whoever does not: a camped lane has to hide and warn, and the other two lanes know they have one enemy jungler fewer to worry about. Saying "camping" rather than "gank" says all that in one word.