Omega (Ω ω) (literally, big O) is the 24th and last letter of the Greek alphabet. In the Greek numeric system it had a value of 800.
Omega is used to denote an end to something, the opposite being Alpha, beginning. For example, "I am Alpha and Omega, the beginning and the end, the first and the last." (Revelation 22:13, KJV)
Omega has been used as the name for a wide variety of other things, for example:
The upper-case letter Ω is used as a symbol for:
The lower-case letter ω is used as a symbol for: