Hosting Models
Colocation
Renting rack space, power, and network in a data center for hardware you own and maintain yourself.
Colocation is renting the building, not the computer. You buy and own the servers, then pay a data center for rack space, power, cooling, and a network uplink. Staff there provide remote hands when you can't drive over, but the hardware is yours to spec, upgrade, and replace.
This model made more sense before cloud pricing got competitive. Today it appeals to organizations with heavy, steady workloads where owning the gear beats renting it for years, or with compliance rules that demand physical custody of the hardware.
For almost everyone building a website or app, colocation is the wrong tool. The capital cost, the hardware lifecycle, and the operational burden are exactly what cloud hosting and VPS providers exist to absorb.