The term 'FIRST IN ORDER' can be summarized by two crossword solutions: PRIME (5 letters) and FOREMOST (8 letters). PRIME is an adjective that means 'of the highest quality, degree, or importance'. It is often used to describe a person or thing that is the most important or influential in a particular situation. FOREMOST is an adjective that means 'most important, prominent, or influential'. It is often used to describe someone or something that is the leader or most prominent in a particular field or activity.