Organic compounds contain carbon and hydrogen. They also often contain oxygen, nitrogen, phosphorous and/or sulfur. Most inorganic compounds don't contain carbon and hydrogen.
The molecules that make up living things are organic. These include proteins, carbohydrates, fats and nucleic acids. Petroleum products are also organic compounds. They are made of chains of various lengths of carbon atoms bonded to each other and also bonded to hydrogen atoms. Natural gas, gasoline, kerosene, oil and parafin wax are all examples of organic compounds from petroleum sources. There are other categories of organic compounds such as alcohols and benzene-based compounds.
Most compounds from non-living sources, such as rocks and minerals, are inorganic. Silicon Dioxide is an example of an inorganic compound that is found in abundance in nature.
Organic Chemistry is the branch of chemistry that studies carbon and hydrogen containing compounds and the reactions they undergo. About 90% of known compounds are organic.