(a corruption arising from a wrong division of "a napron" into "an apron," from the Fr. naperon, napperon, a diminutive of nappe, Lat. mappa, a napkin), an article of costume used to protect the front of the clothes. It forms part of the ceremonial dress of Freemasons. The "apron" worn by church dignitaries is a shortened cassock. The word has many technical uses, as for the protecting slope in front of the sill of dock-gates, or at the foot of weirs.