Copyright is a legal concept, enacted by most governments, giving the creator of an original work the exclusive rights to it, usually for a limited time.
Generally, it is "the right to copy", but also gives the copyright holder the right to be credited for the work, to determine who may adapt the work to other forms, who may perform the work, who may financially benefit from it, and other related rights. It is a form of intellectual property (like the patent and the trademark) applicable to any expressible form of an idea or information that is substantive and discrete.
Copyright protects works like novels, computer programmes, plays, sheet music and paintings. Generally, the author of a copyright work has the right to reproduce, publish, perform, communicate and adapt his work.
These exclusive rights form the bundle of rights that we call copyright and enable the owner to control the commercial exploitation of his work. Copyright can be transferred either as an entire bundle, or as a single, distinct right within the bundle.
For a work to be protected by copyright, it has to be original and expressed in a tangible form such as in recording or writing. Originality simply means that there is a degree of independent effort in the creation of the work.