The Collaborative International Dictionary of English v.0.48:

Pavis \Pa*vis\, Pavise \Pa*vise\, n. [OF. pavaix, F. pavois; cf.
   It. pavese, LL. pavense; perh. named from Pavia in Italy.]
   (Mil. Antiq.)
   A large heavy oblong shield covering the whole body, carried
   by a pavisor, who sometimes also screened an archer with it.
   It was originally carried but sometimes set up in permanent
   position [Written also pavis, pavais, pavese, and
   pavesse.] --Fairholt.
   [1913 Webster + WordNet 1.5]

WordNet (r) 3.0 (2006):

pavise
    n 1: (Middle Ages) a large heavy oblong shield protecting the
         whole body; originally carried but sometimes set up in
         permanent position [syn: pavis, pavise]