You just figured out the appropriate moniker to call your father-in-law. While it may not be "daddio", you're jumping in with your place in the family (and figuring out the family dynamics as you go.) Now it's time to find a Christmas gift for the man who sits at the head of the table - your father-in-law. This guide to finding Christmas gift ideas for a father-in-law will help steer your search, so you can be confident in your choice.
