Jesus is the "
alpha" and the "
omega", the "
first" and the "
last".
Revelation 22:13 I am Alpha and Omega, the beginning and the end, the first and the last. [kjv]
εγω το αλφα και το ω ο πρωτος και ο εσχατος η αρχη και το τελος [gnt]
"Α" ≈ "alpha" is the
first letter of the Greek alphabet.
"Ω" ≈ "omega" is the
last letter of the Greek alphabet.
The Chrismon "IHS" is often taken to say "In His Service". "ΙΗΣΟΥΣ" ≈ "Jesus" which, in English, is "IHSOUS". The first three letters are (uppercase) "IHS" or (lowercase) "ihs".