The dictionary defines copyright as:

the exclusive right  to make copies,  license, and otherwise exploit a literary, musical, or artistic work, whether printed,audio, video, etc.: works granted such right  by law on orafter January 1, 1978, are protected for the lifetime of the author or creator and for a period of 50 years after his or her death.

In simpler terms, when you own the copyright to a piece of work, you literally have the right to produce copies of that work. You also have the right to license the work to others who would like to use it, as without your permission it would copyright infringement. Its basically a form of intellectual property law that protects an original piece of work from being pirated or used without permission. 

Copyright law originated in the United Kingdom from a concept of common law; the Statute of Anne 1709. It became statutory with the passing of the Copyright Act 1911. The current act is the Copyright, Designs and Patents Act 1988

Rights covered

- The law gives the creators of literary, dramatic, musical, artistic works, sound recordings, broadcasts, films and typographical arrangement of published editions, rights to control the ways in which their material may be used.

- The rights cover; broadcast and public performance, copying, adapting, issuing, renting and lending copies to the public.

- In many cases, the creator will also have the right to be identified as the author and to object to distortions of his work.

- International conventions give protection in most countries, subject to national laws.