What does tropic caner mean?

Answer 1

Nothing.

The "Tropic of Cancer" is a circle of latitude, an imaginary line parallel to the Equator, about 23° 26' north of the equator. It is at this latitude that the Sun appears exactly overhead at the summer solstice.

South of the equator there is the "Tropic of Capricorn"

The 'Cancer' and 'Capricorn' in these names comes from the constellation in which the sun would appear to be at the Summer and winter solstices respectively (if you could see the Sun and the stars at the same time then).