Definition
Hashrate represents the speed at which a mining device can perform the SHA-256 hashing algorithm. It is the single most important performance metric for any mining device.
Common units: H/s, KH/s (kilohash), MH/s (megahash), GH/s (gigahash), TH/s (terahash), PH/s (petahash), EH/s (exahash). Each step is 1,000x the previous unit.
A higher hashrate increases the probability of finding a valid block hash and earning the block reward. Network hashrate refers to the combined computational power of all miners on the Bitcoin network.
In Simple Terms
The speed at which a mining device performs calculations. More hashrate equals more mining power.
The computational power of a mining device, measured in hashes per second (H/s). Higher hashrate means more chances of finding a block.