Let’s imagine you have a table with at least two columns. For each entry in the first column, there’s a corresponding value in the second column in the same row. If you want to find out the value for a certain entry, you can either manually scroll down the rows or you can search for it with the LOOKUP function. Enter the search term into the formula and Excel will give you the relevant value. Alternatively, you can also create a formula with a search field. You can then easily integrate the cell with the search term into the LOOKUP formula.
This direct application of the function is already very useful. But combining LOOKUP with other functions is even more practical. Nesting allows you to either pull the search term from the result of another function or to pass on the found value to another function for further processing.