Floating point
A number that is not a whole number (3.14, for example) but that is recorded without the use of a fixed decimal point. Computers use this method of storing numbers so that they can calculate a large amount of varying numbers quickly. To get rid of the decimal point, the whole part of the number is treated separately from the fractional part of the number, which is then multiplied by a base 10.

The problem with a floating point is that it is approximate -- i.e. when missiles miss their target by a few feet, that's very likely to be a result of using floating point numbers. (Also see Top down programming