A gite is a self-catering holiday rental accommodation. Usually a cottage with several rooms, with the owner living close by (but it can also be in the owner’s house itself, with a room or more available for rent).
A gite usually has everything equipped (washing machine, kitchen, utensils, etc), but you need to clean the rental yourself, do the beds and cook. At the end of the rental, you need to return the place to the way it was when you entered.
There is one very large organisation that covers all of France for gite rentals. Called “Gites de France“, they apply a star systems to each rental (called “Epis”), with 5 being “luxury”.
The good part of using gites is a) cost is lower than hotels and b) many offer several rooms, so if you are travelling with several people, you can unit them all under the same roof with no fear of disturbing other guests and c) you’ll find gites all over France, even in the smallest villages where there are no hotels.
Some gites offer “Table de Hotes”, i.e. you eat at the owner’s table (pots luck).