Definition:Part

Definition

Of Integer

An aliquot part of an integer $n$ is a divisor of $n$ which is strictly less than $n$.

Of Real Number

In the words of Euclid:

A magnitude is a part of a magnitude, the less of the greater, when it measures the greater.

(The Elements: Book $\text{V}$: Definition $1$)

Also defined as

A part is also used to mean a portion, or segment, cut off from a quantity.