The term 'GREAT IN NUMBER' can be described by three words: LEGION (6 letters), LION (4 letters), and MULTITUDINOUS (13 letters). LEGION is a Latin word meaning a large group of people, usually referring to a military unit. A LION is a large wild cat, known for its strength and power. MULTITUDINOUS is an adjective meaning very numerous or great in number. All three words describe a large quantity of something, making them appropriate solutions for the term 'GREAT IN NUMBER'.