The term 'FIRST IN LINE' refers to a person or group of people who are in the highest position of authority or power. The crossword solutions for this term include ELDEST (6 letters), NEXT (4 letters), HEIR (4 letters), ELL (3 letters), HEAD (4 letters), and NEXTUP (6 letters). ELDEST is an adjective meaning the oldest or most senior member of a family or group. NEXT is an adjective meaning immediately following in time, order, or sequence. HEIR is a noun referring to a person who legally inherits the property of another after their death. ELL is a noun referring to an old unit of measure, usually equal to 45 inches. HEAD is a noun referring to the leader or chief of a group or organization. Finally, NEXTUP is an adjective meaning the NEXT in line or the NEXT in succession.