The marketing funnel is a way of organizing the journey that takes customers from the initial awareness stage of your business all the way through to the point where they're ready to purchase.
If you think about it, recruitment works in a very similar way. It can be a long process moving from the first point a candidate sees your opportunity to when they actually start their new job. Candidates need to be carefully nurtured through this funnel just like leads are nurtured by marketers.
There are 4 major stages of the recruitment funnel:
Attract (capture the interest of job seekers with some sort of job advertisement)
Recruit (persuade candidates that this role is the right job for them)
Onboard (make sure the candidate settles into their new role smoothly)
Retain (ensure your candidates remain engaged in their new employment)