An archaic or dialectal name, possibly for butter churning equipment or a type of medieval military machine designed as a battering device.
Possibly from butter + -is, or from Old French bateriz, relating to battering devices. The etymology is uncertain as the term appears only in very old texts.
When words appear just once or twice in old manuscripts, historians have to become detectives—butteris might be a variant of battering ram, or a cheesemaker's tool, and we may never know for certain.
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