- P – Political
- E – Economic
- S – Social (cultural)
- T – Technological
PEST Analysis is a framework of above points (or micro-environmental factors) used for the understanding of micro-environmental factors which might lead you to do major strategic changes.
You will come across many similar abbreviations for the almost same thing - STEP, PESTEL, PESTLE, PESTE, PESTLIED, SLEPT, STEEPLE, STEEPLED, LE PEST C or LEPEST
More readings here:
Have a look at SWOT Analysis also.