"Carbs" in this context is referring to foods that have a high carbohydrate content, like potatoes, yams, bread, pasta, and to a lesser extent things like carrots, beets, parsnips etc. Foods to avoid if trying to keep carbohydrate intake below 20-50, as these diets typically require.

It doesn't refer to cruciferous/fibrous veggies, as well as things summer squash, even though they are almost entire carbs, because the carb content per serving in these foods is quite low - low enough that you can probably eat as much of them as you like and still be within the prescribed range.