Common interest rates used as the basis for product types
BBR - Bank (of England) Base Rate. This rate is set monthly by the Bank of England monetary committee.
SVR - Standard Variable Rate. This rate is set by individual lenders and so it varies between lenders.
LIBOR - London Interbank Offered Rate. A reference rate used for lending between financial institutions.
 
Common product types
Fixed rates do not change.
Variable rates do change. This is usually in response to changes in one of the basis rates above. The basis rates above are all variable rates because they can change. Three types of variable rate are described below.
Capped rates will not rise above an upper limit, the cap. This product type can also have a lower limit below which the rate will not fall, known as the floor or collar. eg a capped rate of 7.0% will vary with a basis rate but will not rise above 7.0%
Discount rates offer a certain discount off one of the basis rates (usually SVR). eg SVR-0.5% means the rate will always be 0.5% less than that lender's SVR.
Tracker rates mirror the changes of one of the basis rates (usually BBR), plus or minus some amount. eg BBR+0.25% means the rate will always be 0.25% more than BBR.
 
Any of the above product types may be offered for a defined period and then change. For example a lender may offer a two years fixed rate which then changes to their SVR for the remainder of the mortgage term.