what’s the meaning of deregulation?

Some industries are regulated, ultimately by the government, but often through a statutory regulator. For example, in the UK power and telecommunications industries (amongst others) have regulators to ensure that proper service levels are adhered to. The regulator can also investigate the way prices are set and often has to give permission for a new business to be set up. Fully state owned enterprises are even more regulated.

If a business is deregulated it really means that it is moving more towards a normal company in which market forces rule and with little or no interference from a regulator.