Definition of "mantelletta"

We were without comestibles, and we had no garments except those we wore, not even a shirt, and the habits, such as they were, were most inconvenient for travelling; for the Pope [Pius VII] wore his mozzetta and stola, and I [Bartolomeo Pacca] the rocchetto and mozzetta, together with the mantelletta.

1850 August 31, “Historical Memoirs of Cardinal Pacca, Prime Minister to Pius VII. Written by Himself. Translated from the Italian, by Sir George Head. 2 vols. Longman & Co.”, in The Athenæum: Journal of English and Foreign Literature, Science, and the Fine Arts, number 1192, London: Printed by James Holmes, Took's Court, Chancery Lane; published at the Office, 14 Wellington Street North, Strand, by J. Francis, page 921, column 2

In Rome the cardinals wear the mozzetta over the mantelletta, except in their titular churches, when it is worn immediately over the rochet.

1912, “The Cardinals of the Roman Catholic Church”, in Herman Joseph Heuser, editor, The Ecclesiastical Review: A Monthly Publication for the Clergy, volume XLVI, Philadelphia, Pa.: American Ecclesiastical Review, page 145

In the presence of the Pope and within the Archbishopric of Rome, the cardinals and the bishops had to conceal the rochet beneath a so-called mantelletta, a knee-length coat, which was open at the front.

2015, Philipp Zitzlsperger, “A Change in Forms and the Migration of Bodies in Rome – From the Cardinal’s Tomb to the Cenotaph”, in Tarald Rasmussen, Jon Øygarden Flæten, editors, Preparing for Death, Remembering the Dead, Göttingen: Vandenhoeck & Ruprecht, page 84