PE

PE is a common abbreviation. 
Geography
The top-level-domain of Peru
Pernambuco, one of the states of Brazil
Prince Edward Island, one of the Provinces of Canada
Port Elizabeth, a city in South Africa
The post code for Peterborough, in the United Kingdom

Economics
Private equity
Price–earnings ratio 
P/E ratio

Science, medicine, and therapy
Premature ejaculation
Penis enlargement
Physical education
Phenylephrine, a drug
Phosphatidylethanolamine, a class of substances found in cell membranes
Pulmonary embolism
Pleural effusion
Phycoerythrin, a protein
Polyethylene, a common plastic polymer
Potential energy
 Present Era, a year numbering system commonly used in archaeology that uses 1950s as the epoch marker
 Probability of exceedance, probability calculations in earthquake and disaster hazard analysis
 Prolonged exposure therapy, a form of behavior therapy designed to treat posttraumatic stress disorder
 Protective earth, a type of electrical protective system
 Phenytoin equivalent, used to measure doses of fosphenytoin
 pE, the negative logarithm of the electron activity