IoT devices are considered embedded devices, which in short means a computer attached to something else, whatever that something else might be. This is in contrast with laptops, desktops, and servers, for which the computer in them is the end and not just the means.
While these terms are not formal terms, a common way to distinguish IoT devices from other embedded devices is by the presence of network connectivity. This means that IoT devices can talk to other IoT devices, or to your desktop, or to some server in the cloud.
Some of these devices are low-cost consumer devices (for example light bulbs and light switches for the home) or are very purpose oriented (such as a fridge or oven, or the Amazon dash button). And others, while not as price sensitive or as single-purpose, have been developed by teams with little to no experience in network, which in turn have not taken full advantage of the networking capabilities of these devices.
Read more at IoT for all