What is the junction object and what purpose does it serve in Salesforce?

Junction objects are used to build many-to-many relationships between objects. For example, the user can take a recruiting application where a position for a job can be linked to many candidates or can take a candidate and link the candidate to many other jobs. In order to connect the data model, a third party object is referred to as junction object. In the given example, the junction object is “job application.”