Microsoft Excel: Is there a symbol that represents the value of the row or column and can be used in defining functions?

Microsoft Excel: Is there a symbol that represents the value of the row or
column and can be used in defining functions?

I am dealing with an incredibly large stack of data (close to a 1000
rows). I want to write a function for all of the cells in a column that
takes the value from one cell in each row, divides it by the value from
another cell in the same row, and writes the result on a third cell in the
same row. In other words, as to row X, it takes AX, divides it by BX, and
writes it on CX; and as to row Y, it takes the value in AY, divides it by
BY, and writes on CY.
As I said, I am dealing with a large stack of data and I really would like
to be able to write one function for the entire column, rather than having
to write one function for each cell in the column. Conceptually, it is
clear to me that I need some way of using the row number as the variable
in defining the function and apply that to the entire column. I do not
know how to bring that to application though.
Thanks in advance for your help.
P