i AER stands for Annual Equivalent Rate and illustrates what the interest rate would be if interest was paid and compounded once each year. As every advertisement for a savings product, which quotes an interest rate, will contain an AER you will be able to compare more easily what return you can expect from your savings over time.
ii Net rate is the contractual rate of interest payable after the deduction of income tax at the rate specified by law (currently 20%).
iii Gross rate is the contractual rate of interest payable before the deduction of income tax at the rate specified by law.
iv Tax-free is the contractual rate of interest payable where interest is exempt from income tax. Tax treatment depends on your individual circumstances and may change.