A Geocode is a term to describe a geophysical location on the earths surface, expressed as a latitude and longitude. There are many kinds of geocode depending on the country you're in. For the UK, and for address validation purposes there are :

Rooftop / Premise Level Geocodes

Postcode / Street Level Geocodes

Our Rooftop Geocodes are provided by Ordnance Survey and include a number of other address attributes such as UPRN, which help couriers and logistics companies not only deliver to the right location every time, but are also used in automated route planning for optimised routing and delivery solutions.

You can find out more about our Rooftop Geocodes here : https://fetchify.com/data-intelligence-tools/geocoding/