What makes food or a farm organic? Are there strict guidelines for what can be called organic?
How does food qualify as organic?
The FDA has regulations for what food products can be labeled organic and what can't. Typically, these are strict regulations on the use of chemicals anywhere near where the product is grown, whether these chemicals are used for pesticides, fertilizers, and even treatment of illnesses. For organic produce, none of these chemicals can have a chance of appearing on the farm. For livestock, they must both be fed organically, and also be kept free of the chemicals themselves. An organic farm is one that has been inspected and approved as following these regulations. The inspection includes looking to see if chemicals might enter the farms incidently, like pesticide blowing over from the neighbor's yard. Food from these farms can then be sold as organic.
Like many words, "organic" has different definitions, including what some health-food advocates call "organic" which tends to mean grown naturally, without using anti-pest chemicals or chemical fertilizers, but there's not a clear universal legal definition of this. More recently, some scientists state that eating organic does not improve health as others claim it should - an open question.
More generally (and scientifically), organic means carbon-based, including organic molecules which make up almost all life as we know it. Will be interesting to find out if other planets have non-carbon life forms :-) Web searches can give you all the info you need on "organic".