1
general::
Shared beliefs or interests, a foundation for mutual understanding. For example, The European Union is struggling to find common ground for establishing a single currency. [1920s]
American Heritage Idioms
2
general::
noun VERB + COMMON GROUND have, share The people on the course all share a lot of common ground. | establish, find | find yourself on PREP. on ~ We found ourselves on common ground on the question of education. | ~ between to find common ground between the two sides PHRASES an area of common ground
Oxford Collocations Dictionary