Culinary definition of chop: To cut into small, uniform size pieces with a knife or chopping device.
C@H FOOD FOR THOUGHT
Good knife work is a foundation of good cooking and pleasing presentation. It is worth noting then that a 'chop' is much larger than a dice or a mince, though chop and dice are sometimes interchangeable when the size is specified - as in 'chop to 1/2-inch dice'.
You might also want to purposefully 'rough chop' ingredients for rustic presentation. Generally speaking though, a variety of chopped ingredients should be more-or-less consistent in size. Do the best you can at least, because fruits, vegetables and meats don't come in nice tidy, uniform-shaped bundles for chopping. Use good sense and ask yourself how big a chunk of onion do you suppose would present best alongside small cubes of potato.