Acropolis - The high point or citadel of an ancient Greek city, like the Acropolis in Athens. It is generally a raised area above the rest of the city where the most important sacred and secular buildings are brought together. The buildings on the Athenian Acropolis were important for trade and worship.
Bitcoin is a digital currency (also called crypto-currency) that is not backed by any country's central bank or government. Bitcoins can be traded for goods or services with vendors who accept Bitcoins as payment.
Bitcoin is pseudonymous, meaning that funds are not tied to real-world entities but rather bitcoin addresses. Owners of bitcoin addresses are not explicitly identified, but all transactions on the blockchain are public.