common
Happening often or found in many places; usual or ordinary.
Common means widespread, ordinary, or shared by many people. When something is common, you'll find it frequently or in many places. Robins are common birds in North America because you see them in yards and parks everywhere. Colds are common illnesses because most people catch one several times a year. A common mistake is one that many people make, like confusing “their” and “there.”
The word can also mean shared or joint. A common goal is something multiple people work toward together, like when a class shares the common goal of putting on a great school play. Common ground refers to interests or beliefs people share, which helps them understand each other and work together.
When people have something in common, they share it. You might discover you have a favorite book in common with a new friend, which gives you something to talk about.
Less commonly, common can mean relating to ordinary people rather than royalty or the wealthy. In medieval England, commoners were regular people, while nobles had special titles and privileges. The British House of Commons gets its name from representing common citizens rather than hereditary lords.