what's the formal name for

kimberleigh30

LEO?

 Just Leonardo?

 

JLG95

Or Leon.  Or Leopold.

Sept1799

EllaHella:

Or Leonard.

This is what I was thinking.

stgn01

I always thought it was Leonard.  But I have a good friend and his name is just Leo.  It's not short for anything.

FrickandFrack

Leonard or Leonardo? 

MelianLuthien

I'm a lurker, but I just wanted to chime in. 

"Leo" is a full and formal name, all by its cute little self.  We have one, and his name wears very well.

But, if you really wanted a longer form:

Leopold

Leonard

Napoleon

Leon

Leander

Lionel

Leonidas