The term 'last in a series' can be expressed in four different ways: OMEGA (5 letters), ZEE (3 letters), NTH (3 letters), and ENDMOST (7 letters). OMEGA is the last letter of the Greek alphabet, and is often used to symbolize the end of something. ZEE is an informal way of saying the letter Z, which is the last letter of the English alphabet. NTH is an abbreviation for the word 'ninth, ' which is the last number in a series of ten. ENDMOST is an adjective meaning furthest from the center or the most extreme. All four of these words can be used to describe the concept of being the last in a series.