Numerator (noun)

1. The top part of a fraction, representing the number of parts being considered.
2. A quantity or measurement that is being counted or considered in a mathematical operation or calculation.

Origin:

Derived from the latin word numerare, meaning 'to count', and is used in mathematics to describe the top part of a fraction that indicates the number of parts being considered.

Examples:

1. The numerator of the fraction is the number of pieces being counted.
2. The numerator of the fraction 2/3 is 2, indicating that two parts out of three are being considered.
3. The numerator of the fraction must be an integer.
4. The numerator was used to calculate the average of the data set.
5. The numerator and denominator of the fraction must have a common factor to simplify it.