The term 'long stretch of time' can be represented by three different words in a crossword puzzle: EON (3 letters), AEON (4 letters), and AGES (4 letters). EON is a very long period of time, usually millions of years. AEON is a synonym for EON, but it is also used to refer to an indefinite or immeasurable period of time. AGES is a less specific term than EON and AEON, and it is used to refer to a period of time that is longer than usual.