Pronunciation: \ˈbär-bi-ˌkyü\ Function:transitive verb
Inflected Form(s):bar·be·cued; bar·be·cu·ingEtymology:2barbecue
Date:1690 1 :
to roast or broil on a rack or revolving spit over or before a source of heat (as hot coals) 2 :
to cook in a highly seasoned vinegar sauce
— bar·be·cu·er noun
From Websters dictionary.
Doesn't say anything at all about tomatoes, mustard, beef, pork or anything else. Just the process. And the vinegar and spices.