What is overclock

What is overclocking? Is it a software thing or do I have to tweak the hardware? Is it safe?
Someone please explain these queries in simple english.
PS- Don’t bother to reply “google it”
Answer #1
How can you not expect someone to say Google it when such a simple question is asked?
Answer #2
Its making your PC perfomances much better.Mostly in BIOS but you have some softwares too,depends from hardware
Answer #3
most graphics cards come with overcloking softwares included, so you can customize it from your pc. just make sure you have enough power and enough fan speed.
good luck
Answer #4
its basically like the name of ti suggests. its changing the clocks speeds to over what the factory defaults are set at. you can damage your hardware if u dont know what your doing so dont just jump into it read up first
Answer #5
here you go
http://en.wikipedia.org/wiki/Overclocking