Epoch
An epoch is a life cycle marked by halving events (4 years cycle for Bitcoin).
Related terms
EAL (Evaluation Assurance Level)
An Evaluation Assurance Level (EAL) is a category ranking assigned to an IT product or system after a Common Criteria security evaluation. The level (1 to 7) indicates to what extent the product or system was tested.
Efficiency
Efficiency measures how effectively a mining device converts energy into hashrate.
Efficiency Delta
Efficiency delta compares the reported hashrate of a miner to the hashrate reported by its pool.