The term 'BIRR' is a currency used in ETHIOPIA, which is 8 letters long. PEP is an abbreviation for Positive Enthusiasm and Persistence, which is 3 letters long. VIGOR is an energetic strength or force of body or mind, which is 5 letters long. ENERGY is the capacity for doing work, which is 6 letters long. POTENCY is the power or capacity to produce an effect, which is 7 letters long. ETHIOPIA is a country in East Africa, which is 8 letters long.