'Carbs' is short for carbohydrates - carbohydrates are "any of various neutral compounds of carbon, hydrogen, and oxygen (as sugars, starches, and celluloses) most of which are formed by green plants and which constitute a major class of animal foods." Whew! Foods high in carbohydrates tend to be things like pasta, bread, rice, etc. though fruits and vegetables - bananas, potatoes, mangoes, and dates spring to mind - can also be pretty high carb.
Conventional wisdom tends to suggest eating plenty of whole grains, fruits, and vegetables in a low-fat, moderate-to-high carb diet, and there's a whole bunch of variation on either side of that. Some people claim great success with SUPER high carb diets (like fruit-based raw veganism) and some people have had more success with things like very low carb paleo - I've heard of some people who even swear by a zero carb diet, though I haven't met any personally and it's not something I'm willing to try.
As far as I know, pretty much everybody recommends staying away from white, highly-processed carbohydrates (white rice, white bread, white sugar, etc.) but beyond that you're going to have to do some reading, play with macronutrient ratios, and try to find what works for you!