Direct discrimination is when you are treated less favourably because of your race.

Indirect discrimination is where there are rules or conditions which apply to everyone, but which affect one group of people more than others, where there is no good reason for the rule. For example, a company rule that employees must not wear headgear could exclude Sikh men who wear a turban.
Victimisation

If you want to complain about being discriminated against (or if you are helping a colleague who is complaining), you may fear that your employer may, for example, treat you less favourably for this reason. If they do, this is called victimisation, and is unlawful in the way discrimination is.