A nonterminating decimal refers to any number that has a fractional value (numbers to the right of the decimal point) that will continue on infinitely. The most well-known example of one of these numbers is pi; another example is 1/3, which is 0.333 with the three repeating forever. A nonterminating decimal is indicated by placing a short bar (ellipsis) over the final two decimal values that are recorded.
Most fractional numbers do have a finite amount of digits following the decimal point and are called terminating decimals. An example of a terminating decimal is 1/4, which yields 0.25. Note that nonterminating decimals may frequently be referred to as recurring decimals.