The two terms can mean different things to different depending on what your talking about
To a chemist Organic means it contains carbon, so if you have a nutrient, such as N,K,P bound to carbon a chemist would say its organic, however Rock phosphate does not contain carbon would not be considered or organic to a Chemist. Now consider gasoline, It contains carbon, so is considered organic to the CHEMIST... Now in agriculture the two terms mean something different a organic farmer would not consider gasoline to be organic, and would never but it on his garden. He would however use rock phosphate, or granite dust to supply phosphorus and potassium to his soil, and although, it does not contain carbon (at least not much) it would still be considered organic farming.
so to a farmer organic means supplying the soil and plants nutrients through natural occurring compounds in the soil, or from recently decayed plant or animal matter