Find the Italian words that answer the following English dictionary definitions:
an imaginary line running along the earth's surface from the North to the South Pole, lying everywhere exactly in a north-south direction  
an imaginary line obtained by slicing the earth's surface with a plane parallel to equatorial plane 
the angular distance on the earth east or west of a meridian from the standard meridian which passes through Greenwich 
the point in the heavens vertically above a person on the earth 

– meridiano
– parallelo
– longitudine
– zenit