submarine, pigboat, sub, U-boat
['mink', 'gasmask, respirator, gas helmet', 'platypus, duckbill, duckbilled platypus, duck-billed platypus, Ornithorhynchus anatinus', 'sandbar, sand bar', 'wombat', 'trolleybus, trolley coach, trackless trolley', 'coil, spiral, volute, whorl, helix']