Organic compounds are compounds composed primarily of carbon and hydrogen but also composed of oxygen, nitrogen and, to a lesser extent, phosphorus and sulfur. Historically these were compounds were only isolated from living or once living organisms. These compounds could not be synthesized in laboratories until Friedrich Wohler did so successfully in 1828.
Inorganic compounds were compounds composed of the rest of the elements. These were isolated from rocks and minerals. The difference in source of these compounds, lends to the naming of the compound and the relation to the word organic and living.