Pre covid you could smoke cigars in the outside area of the Meridian on the Dream and Fantasy. Not sure if that's still the case though.There is a designate smoking area on each ship. I don't smoke, so I can't tell you where they are, but they are there. I suspect if you look on the deck plans on the DCL website you will find them.
EDIT - From DCL Website
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Yea, this is still the casePre covid you could smoke cigars in the outside area of the Meridian on the Dream and Fantasy. Not sure if that's still the case though.