These two roles get confused constantly, and the distinction matters:

• Authoritative DNS is the source of truth for a domain: the nameservers (What Is a Nameserver?) that actually hold the real, definitive records for that specific domain. When you change a DNS record, you're changing it at the authoritative level.

• Public (recursive) DNS is the layer that does the asking on your behalf: servers like Google's 8.8.8.8 or Cloudflare's 1.1.1.1 that your device or ISP queries first, which then track down the authoritative answer and cache it for a while so the next person asking doesn't have to repeat the whole lookup.

This is also why a DNS change doesn't appear everywhere instantly: it's correct the moment it's made at the authoritative level, but public recursive resolvers around the world are still holding onto a cached version of the old answer until that cache expires. See Why DNS Changes Take Time to Go Live for exactly what controls how long that takes.