Community Cloud is an online social platform that enables companies to connect customers, partners, and employees with each other and the data and records they need to get work done. It is like a website given by salesforce with which only authenticated community user can login and get salesforce data in hand. We can attach the salesforce community URL with the already existing static website of URL.
A community cloud in computing is a collaborative effort in which infrastructure is shared between several organizations from a specific community with common concerns (security, compliance, jurisdiction, etc.), whether managed internally or by a third-party and hosted internally or externally.