per ‧ i ‧ scope /ˈperəskəʊp, ˈperɪskəʊp $ -skoʊp/ BrE AmE noun [countable]
[ Date: 1800-1900 ; Origin: peri- (from Greek ; PERICARDIUM ) + Greek skopos 'look' ]
a long tube with mirrors fitted in it, used to look over the top of something, especially to see out of a ↑ submarine