sakko

From Sack (“sack”), which was used in the 19th century to refer to an unwaisted jacket; compare English sack coat. This name was due to the loose fitting, possibly reinforced by the idea of it being unpretentious and humble (compare Sack und Asche, English sackcloth). The later alteration of the form on the basis of Italian sacco was intended to have the opposite effect, namely to make it sound fashionable.