Why is it that when you want to use your Television, Stereo, etc, you turn it on, but when you want to use a computer, you boot it, and to restart it you reboot it. Do the older computers have bootprints on the front of them or something? 
When a computer is turned on, it has to load a set of instructions–“software”–to tell it what to do; among other things, to tell it how to load its own operating system. This is called “booting” in reference to the old saw about pulling oneself up by one’s own bootstraps.
Your toaster oven, light bulbs, etc. don’t have software, so they don’t need to be “booted”, just “switched on”.
A lot of home appliances and other gadgets (such as mobile phones and PDA’s) also needs booting because they contain embedded microcontrollers. They do not switch on like a light but with a slight delay.
This delay is most obvious with game consoles and arcade game machines.
When I first started using a PC, I likened “booting” to a “kick in the guts” - an Australian expression for starting an engine. 
Just because I came in too late to answer the actual question, I’ll give a bit of history.
In the old days, booting wasn’t automatic. The human starting the machine had to manually enter a program, the bootstrap loader, that was smart enough to hand control off to another program, which would then start up the OS or the application. This was accomplished through toggle switches on the front of the box, which meant you were entering the program in binary directly into RAM. Great effort was expended to make these bootstrap loaders as small as possible. Nowadays, bootstrap loaders are in ROM or EPROM (Erasable Programmable Read-Only Memory), so booting is just a matter of pushing a button and waiting.