omega; Ω, ω +

(Greek: the 24th and last letter of the Greek alphabet; Ω, ω; the ending, the last of anything)

alpha and omega
1. The first and last; signifies God's eternity.
2. The basic meaning of something; the crucial part; the most important aspect of something.

The beginning and the end, the first and the last, as in "She had to master the alpha and omega of the new computer program before she could even begin."

This idiom and its meaning, based on the first and last letters of the Greek alphabet, appears in the New Testament (Revelation 1:8): "I am Alpha and Omega, the beginning and the ending, saith the Lord," where it is repeated three more times.

omega
1. The 24th and last letter of the Greek alphabet (Ω, ω).
2. The vowel sound represented by this letter.
3. The last of any series; the end.
4. Of or characterizing a chemical group or position at the end of a molecular chain; such as, omega-oxidation.
Omega
A worldwide very low frequency (20-14 kHz) continuous-wave radio navigation system of medium accuracy in which eight stations transmit in succession on the same frequency.
Omega Centauri
A large globular cluster in Centaurus, containing over 100,000 stars and stretching 65 light-years across; located about 16,000 light-years distant and appearing to the naked eye as a fuzzy 4th-magnitude star; designated NGC 5139.
omega melancholicum
A wrinkling of the skin above the nose and between the eyebrows that takes the shape of the Greek letter omega (ω), assumed to indicate a state of melancholy.

It occurs as frowning and as a persisting facial expression in depression. Also called Schüle sign (named for Heinrich Schüle, German psychiatrist, 1840-1916).

omega-3 fatty acids
Any of several polyunsaturated fatty acids found in leafy green vegetables, vegetable oils, and cold-water fish; such as, salmon and mackerel.

These acids are capable of reducing serum cholesterol levels and have anticoagulant properties.

Omega-3 fish oil is considered a neutraceutical, a food that provides health benefits. Eating fish has been reported to protect against age-related macular degeneration, a common eye disease.

omega-6 fatty acid
An unsaturated fatty acid in which the double bond closed to the omega (methyl) end of the molecule occurs at the six carbon from ha end.

Major sources are vegetable and seed oils.

omega-9 fatty acid
A polyunsaturated fatty acid found in animal and vegetable fats.
omega-oxidation
A metabolic pathway of fatty acid oxidation involving the carbon atom farthest removed from the original carboxyl group.
omegatron
In electronics, an instrument that photographs and identifies any radioactive gases that remain after an evacuation.

You can see all of the letters of the Greek Alphabet on this page.