The term TIME INTERMINABLE can be broken down into two crossword solutions: EON (3 letters) and INTERMINABLE (12 letters). EON is a noun that refers to an immeasurably or indefinitely long period of time, often used to refer to an era or age. INTERMINABLE is an adjective that means having or seeming to have no end; endless. Together, the two words form the phrase TIME INTERMINABLE, which describes a period of time that is seemingly never-ending.