This can be kind of confusing because when people refer to hosts, they really can be referring to almost any type of networking devices—including workstations and servers. But if you dig a bit deeper, you’ll find that usually this term comes up when people are talking about resources and jobs that have to do with Transmission Control Protocol/Internet Protocol (TCP/IP). The scope of possible machines and devices is so broad because, in TCP/ IP-speak, host means any network device with an IP address. Yes, you’ll hear IT professionals throw this term around pretty loosely; for the Network+ exam, stick to the definition being network devices, including workstations and servers, with IP addresses.
Here’s a bit of background: The name host harks back to the Jurassic period of networking when those dinosaurs known as mainframes were the only intelligent devices able to roam the network. These were called hosts whether they had TCP/IP functionality or not. In that bygone age, everything else in the network-scape was referred to as dumb terminals because only mainframes—hosts—were given IP addresses. Another fossilized term from way back then is gateways, which was used to talk about any Layer 3 machines like routers. We still use these terms today, but they’ve evolved a bit to refer to the many intelligent devices populating our present-day networks, each of which has an IP address. This is exactly the reason you hear host used so broadly.