What is the name of the table operation that standardizes the template structure?

Question

I am struggling to find the proper term for the following table operation:

1. I take the cross product of all years (2018-2021 in our example) and companies (in the left table)
2. left join the original dataset to the newly created dataset (~template)

I aim to have all the years for all companies regardless of how many data points I have.

What would be the best definition to describe what I am doing? Thanks in advance!