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 an intellectual property form (like the patent, the trademark, and the trade secret) applicable to any expressible form of an idea or information that is substantive and discrete.
Copyright initially was conceived as a way for government to restrict printing; the contemporary intent of copyright is to promote the creation of new works by giving authors control of and profit from them. Copyrights have been internationally standardized, lasting between fifty to a hundred years from the creator's death, or a finite period for anonymous or corporate creations; some jurisdictions have required formalities to establishing copyright, most recognize copyright in any completed work, without formal registration. Generally, copyright is enforced as a civil matter, though some jurisdictions do apply criminal sanctions.