The recruitment funnel is a way of picturing hiring as a series of narrowing stages: applied, screened, interviewed, offered, hired. Many people enter at the top, and only one comes out the bottom, with candidates dropping away at each step. Thinking of hiring as a funnel gives you a shared language for where candidates are and how they flow through your process.
Its real usefulness is in the conversion rates between stages, which show you where your process leaks. If a huge share of applicants fall away right after screening, either the top of the funnel is attracting the wrong people or the screen itself is too blunt. If strong candidates drop out between offer and acceptance, the problem is late and probably about pay, speed or experience.
Measured over time, the funnel turns hiring from a series of anecdotes into something you can diagnose and improve. Instead of a vague sense that a role is hard, you can see exactly which stage is costing you candidates and fix that stage. It is the same idea sales teams use to find where deals stall, applied to people.