The Butt surname has roots in England. I have been told there are families with roots in Germany, and the name is also prevalent in Pakistan. I have seen an Irish book of heraldry that states that while the Butt name is present in some numbers in Ireland, it isn’t native.
Matthews' American Armoury and Blue Book, 1911-1923 ed., shows the (English?) Butt Family crest along with this description: "Arms - Argent, two torteaux in chief and a mullet in base gules; a chief nebulee' azure. Crest - A lion holding in the dexter paw a spear broken." I have seen another crest (researched by a company called Halberts, of Bath, Ohio) which may have been researched in an English version of the book, because it is very different from the one in the Armoury.
The name would have several meanings, depending upon origin. I have seen explanations for the English name along these lines: One is that when last names began to be taken they were often representative of what people did (“Miller”) or where they lived (“Rivers”.) “Butt” may have come from our ancestors properties abutting the edge of the manor lord’s territories. Another is it's a derivative representing descendants of Butta.
Other variations are Butts, Butte, Buttes, Bute, Butes and Bhutto (Pakistan.)