- the 15th letter of the Greek alphabet (O, o).
- the vowel sound represented by this letter.
Origin of omicron
< Greek ō mikrón, literally, small o. Cf. omega
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for omicron
Mira, (Omicron Ceti,) in the neck of the Whale, is a variable star.Letters on Astronomy
Newton presented him with one of his publications, entitled "Omicron."The Works of William Cowper
At all events, it was not possible for him to think of anything bad when he called “Omicron.”
Omicron must show her face in the stars from time to time to remind the child of his love.
And then, on the following morning, Sir Omicron also went his way.Doctor Thorne
- the 15th letter in the Greek alphabet (Ο, ο), a short vowel, transliterated as o
from Greek ō mikron small o; see micro-, omega
Word Origin and History for omicron
15th letter of the Greek alphabet, literally "small 'o,' " from Greek (s)mikros "small," from PIE *smik-. Because the vowel was "short" in ancient Greek. Cf. Omega.
Online Etymology Dictionary, © 2010 Douglas Harper
- The 15th letter of the Greek alphabet.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.