A DNS server that answers queries on your behalf by recursively asking other nameservers until it finds the answer. You point your device at a recursive resolver; the resolver does the legwork.
When you type a domain name, your computer sends a query to a recursive resolver (usually your ISP's, or Cloudflare's 1.1.1.1, or Quad9). The resolver doesn't know the answer—so it asks a root nameserver, which points it to a TLD nameserver, which points it to the authoritative nameserver for that domain. The resolver collects the answer and hands it back to you. That's recursion: the resolver recurses through the DNS hierarchy on your behalf.
This matters for privacy and control. Your ISP's resolver logs your DNS queries by default. Many people switch to third-party resolvers (Cloudflare, Quad9, NextDNS) for privacy or filtering. For maximum control, run your own resolver locally using tools like Unbound or Pi-hole.
Recursive resolvers are distinct from authoritative nameservers, which hold the actual zone data. A domain owner configures authoritative nameservers; users query through recursive resolvers.