Similar to benefits in kind, these are usually non-monetary benefits enjoyed by an employee which are not subject to tax. They are incentives to prospective employees or to existing employees where wage increases are not in view. They can also be used to indicate and reward marginal differentials in employment, e.g. at one time the provision of an umbrella stand was indicative of increased status in the civil service. Some of the more common fringe benefits today are staff discounts, social clubs financed by the employer.
Reference: The Penguin Business Dictionary, 3rd edt.