POS, or Proof of Stake, is a consensus method selecting validators based on staked coins.
PPLNS rewards miners based on the number of shares contributed to the last N shares.
PPS is a mining pool payout method compensating based on contributed hashrate.
A PSU provides power to ASICs and may be external or integrated.
Payback period is the time it takes for mining hardware to generate revenue equal to its cost.
PoW is a consensus method using computational work to validate blockchain transactions.