ARP
In plain terms
A protocol mapping IP addresses to hardware MAC addresses.
Going deeper
ARP resolves a known IP to the MAC address needed to deliver data within a local network. It bridges layer 3 and layer 2 addressing.
Under the hood
Works within a LAN; ARP spoofing is a known attack used in man-in-the-middle scenarios.
Examples
Local delivery, IP-to-MAC resolution, LAN communication, ARP spoofing.
Think of it like...
Like asking 'who has this IP?' on the local network to find their physical mailbox.