Parent / Child from same table?

In the past I've done this using a one to many relationship - continents and countries. So any given continent will have multiple countries, so it makes sense to use a continents table and a countries table.

I have a case here where its a one to one relationship - categories and category orders. Really its a means to an end to allow sorting in something other than A-Z or by unique ID.

In which case is it possible to have a single table for categories:

Category_ID
Category
Category_Order

Where Category can be the Parent, and Category_Order be the Child?

Really just to automate the selection of Category_Order when a user adds a new Category using the dynamic dropdowns.

Hope that makes sense!