the fifteenth letter of the Greek alphabet (?, ?)
Origin of omicronClassical Greek o mikron, literally , small (i.e., short) o: see micron, omega
The 15th letter of the Greek alphabet. See Table at alphabet.
Origin of omicronMiddle English, from Greek o m&imacron;kron, small o (because of its being a short vowel in Greek) : o, the letter o + m&imacron;kron, neuter of m&imacron;kros, small.
(plural omicrons or omicra)