What is Common ?
Common is (adj) 1. which happens often, or which you find everywhere The plane tree is a very common tree in towns. It’s very common for people to get colds in winter. 2. belonging to two or more people The two countries have a common frontier. Blue eyes are not common to all the members of our family. common ownership the ownership of a property by a group of people in common shared by two or more people They have two things in common – they are both Welsh and they are both left-handed. (noun) land which belongs to a community We went walking on the common. (NOTE: now mainly used in names of places: Clapham Common, Wimbledon Common, etc.)
source: Easier English, Student Dictionary Upper Intermediate Level