What does Hashes per Second mean?
Hashes per Second is a measure of how many hashes are produced by a computer in one second. One hash per second is quite small, so there are also denominations of million hashes (known as 1 MH/s) and gigahashes, which is 1 billion hashes per second.
Next comes a terrahash, which is 1 trillion hashes per second and finally we have the petahash, which is one quadrillion hashes per second. The Bitcoin network has reached as high as 33.9 PH/s as of April 2018 and is continuing to grow.