submarine, pigboat, sub, U-boat
['trolleybus, trolley coach, trackless trolley', 'chain mail, ring mail, mail, chain armor, chain armour, ring armor, ring armour', 'sliding door', 'bannister, banister, balustrade, balusters, handrail', 'pedestal, plinth, footstall', 'wing', 'slide rule, slipstick']