I'm not sure I could give you an ironclad definition, but by and large, aromatic tobaccos are tobaccos that are cased with some sort of alcohol based flavoring that produce a pleasant smell when the tobacco is ignited. These flavorings could be anything and everything, from chocolate to fruit to vanilla to any kind of liquor flavorings like rum and whiskey. American style aromatics tend to be pretty heavily cased, meaning that they have a lot of top flavor added, where as a lot of Danish aromatics are not so heavily cased. You also have Lakeland style aromatics, which have a noticeably stronger floral/soapy flavor, where as a lot of other style aromatics don't have much flavor at all, at least to most smokers. Some aromatics that have a good flavor, at least to my tongue, are MacBaren 7 Seas Royal and CAO Moontrance. 1Q also has great flavor and burns really well and is widely available in bulk.