The tag should be used for questions about organic gardening or when organic solutions are requested for a specific problem.
The word "organic" has multiple overlapping meanings and this has led to much confusion. This is not helped by the adoption of the word in 'new age' marketing slogans for quack remedies and the like.
There are three legitimate meanings for the word "organic":
Organic Horticulture and Agriculture This is the primary meaning for this tag on this site. Organic horticultural methods attempt to use natural only methods and treatments. Natural fertilizers (e.g. compost and manure) are used instead of artificial fertilizers; and pests are controlled using selective plants, "benign" chemicals (e.g. soap sprays), and encouraging natural predators. These methods aim to reduce the impact on the larger ecosystem and reduce the potential for toxic chemicals in the food chain.
Many of the divisions as to what is or is not organic are extremely gray, and most gardeners will have to make their own decisions as to what is or is not acceptable. For example, "pyretheum" is an insecticide made from chrysanthemums but is often avoided by organic gardeners - however it is arguably more "natural" than the soap sprays which are usually preferred. The deliberate introduction of predators poses similar dilemmas.
Organic Matter This refers to organisms, dead or live.
Organic Chemicals / Chemistry Organic chemistry refers to all chemistry relating to the carbon atom. This is a very complex and rich subject area. All life is based on organic chemistry - as are virtually all pharmaceuticals and artificial pesticides.