I don’t know if this is a theological question, a denominational question, semantics, or how one was raised.
But are baptism and christening the same thing? Most of the on-line sources imply that they are but I have it in my mind (which means that it is subject to change) that they are different. It may be that because I grew up in the South I think there is a difference.
And for the record, I was baptised as an infant and I have always considered it a valid baptism. We will save the question of who can be baptized for another time.
What are your thoughts on this?
Thoughts From The Heart On The Left 
In my mind these have been interchangeable and are, as you noted probably the result of regional preferences. If you keep digging and find anything more substantive, let the world know!
And yes, the Cardinals are on a roll right now. They do play the Fish very well in South Florida.
Bob,
Thanks for the reply. As another colleague noted, when we christen someone, we are giving them a name, as we christen a ship.
I do not know the history of the words or the difference and have not been motivated to learn. The big difference I do know about is the distinction between baptism and dedication.
This website http://religion.adherents.com/Christianity/20-christening.html suggests the difference is that “christening” is like when we christen a ship — give it a name. But it looks like some people use the terms interchangeably.
Thanks! I found much the same when I did a search before putting up the post. Though I am not sure we would necessarily christen an adult.