Geocoding and Reverse Geocoding? - Google Maps v3

What is the difference between geocoding and reverse geocoding?

Geocoding:

Geocoding is the process of converting a location addresses into geographic coordinates (latitude/longitude)

Example:- Gurgaon Road, Sector 18, Gurgaon, Haryana ---> 28.496718,77.078919

Reverse Geocoding:

Reverse Geocoding is the process of converting geographic coordinates(lat/lng) into a location address.

Example: - 28.496718,77.078919 ---> Gurgaon Road, Sector 18, Gurgaon, Haryana

Usage Limits:

Use of the Google Geocoding API is subject to a query limit of 2,500 geolocation requests per day. (User of Google Maps API for Business may perform up to 100,000 requests per day.)

For more about Google Geocoding visit https://developers.google.com/maps/documentation/geocoding/