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 an innovative payment network and a new kind of money. Bitcoin uses peer-to-peer technology to operate with no central authority or banks; managing transactions and the issuing of bitcoins is carried out collectively by the network. Bitcoin is open-source; its design is public, nobody owns or controls Bitcoin and everyone can take part. Through many of its unique properties, Bitcoin allows exciting uses that could not be covered by any previous payment system.