Infrastructure as a Service (IaaS)
Infrastructure as a Service (IaaS) is a new business model pioneered in the early 2000s that allow anyone to provision infrastructure programmatically and on-demand. Previously to order infrastructure you had to go through a purchase order process to request the infrastructure you needed, wait until it got delivered and installed into a data center, and then test your application once everything was ready. Infrastructure as Service makes this entire process on-demand because now developers and businesses can summon any infrastructure they want, at any time through API’s or easy to use click interfaces to provision the hardware that they need.
in other words
Using the internet for hardware, instead of your office.