Parallel and latitude কী?

Example 14.2 (A navigator at night)

A navigator measures the Pole Star at $41^\circ$ above the northern horizon. The ship is at latitude $41^\circ$ N, about $41 \times 111 \approx 4550$ km north of the equator. Sailing north, she finds the star a little higher each night; sailing south towards the equator, it sinks towards the horizon. South of the equator the Pole Star cannot be seen at all, since it stays below the horizon: there, the noon Sun gives the latitude.

Example 14.5 (Reading the coordinates of Sydney)

On the map, Sydney lies below the equator: it is in the southern hemisphere, a little above the parallel $30^\circ$ S, closer to $30^\circ$ than to $60^\circ$; its latitude is about $34^\circ$ S. It lies to the right of the prime meridian, a little beyond the meridian $150^\circ$ E; its longitude is about $151^\circ$ E. We write: Sydney, $34^\circ$ S, $151^\circ$ E.