The term 'ACCUMULATOR' is a 7-letter word that can be defined as an amasser. It is a noun that refers to a person or thing that collects, gathers, or accumulates something. This could refer to a person who collects items such as coins, stamps, or other collectibles, or it could refer to a device that stores energy or power. Accumulators are often used in electrical systems, such as batteries, to store energy for later use.