Broadcast
In plain terms
Sending data to all devices on a network segment.
Going deeper
Broadcast delivers a message to every host on the local network, used for discovery and announcements. Everyone on the segment receives it.
Under the hood
Limited to the local broadcast domain; excessive broadcasts ('storms') degrade networks, hence VLAN segmentation.
Examples
ARP requests, DHCP discovery, network announcements, local segments.
Think of it like...
Like a public-address announcement everyone in the building hears.