Okay, so let's start with what a sheaf is. Imagine you have a big garden with many different types of flowers. A sheaf is like a basket in which you can gather all the flowers of one type (for example, roses) together into one neat bundle. This makes it easy to observe and study the properties of just the roses in your garden.
Now, a divisor is a mathematical object used to study the properties of curves (think of the outline of the garden). It tells you how many times a given curve intersects with the garden. So a divisorial sheaf is like a basket where you gather together all the functions on the curve that have certain properties related to how they intersect with the curve.
Think of it like this- if you wanna understand how many times a specific type of flower intersects or touches a curve, a divisorial sheaf will be used to count that. For example- if you wanna know, how many roses touches a particular part of a curve in your garden. The roses are like the floral components of your divisorial sheaf since you can vary your function across different sections of the curve.
In simple words, the divisorial sheaf is a basket to keep hold of functions that tell us how many times a specific type of flower touches a curve in a garden.