O The sixteenth letter of the Phoenician and early Greek alphabets, the fifteenth in English and the fourteenth in Latin. Between N and O the Phoenician and the Ionic Greek alphabet have a sibilant—in Greek Ξ＝x. The Western Greek alphabet had a different symbol, X, for the sound of x and placed it at the end, as did its descendant the Latin alphabet. The original form of o was a more or less roughly formed circle. The Aramaic ?? and Hebrew ע, which seem so different, arise from a circle left open at the top, U, a form which can be traced in Aramaic from the 5th or 6th century B.C. In the Greek alphabets the circle appears sometimes with a dot in the centre, but in many cases it is doubtful whether this mark is, intentional, or is only the result of fixing a sharp point there while describing the circle. Sometimes O is lozenge-shaped ◊ and rarely (in Arcadia and Elis) rectangular □. In many varieties of the Greek alphabet this symbol was used, as it always was in Latin, for the long as well as the short o-sound and also for the long vowel (in the Ionic alphabet written ou) which arose from contraction of two vowels or the loss of a consonant (δηλοῦτε＝δηλόετε, οἴκους＝οἴκονς). As early as the 8th century Ionic Greek had invented a separate symbol for the long o-sound, viz. Ω. This when borrowed by other dialects showed at first some variety of usage, though practically none in form. As this was placed at the end of the ordinary (not the numeral) Greek alphabet, “alpha and omega” has become a proverbial phrase for first and last. The Greeks themselves, however, did not call Q omega (great o) nor did they call Ω omicron (little o), though these names are given even in modern Greek grammars. The former was called simply o and the latter u (ou, pronounced as oo in moon). The Hebrew and probably the Phoenician name for O was Ain (Ayin), and in the Semitic alphabet, which does not indicate vowels, the symbol stood for a “voiced glottal stop” and also for a “voiced velar spirant” (Zimmern). The most important feature of this vowel is the rounding of the lips in its production, which, according to its degree, modifies the nature of the vowel considerably, as can be observed in the pronunciation of the increasingly rounded series saw, no, who. In Attic Greek Ο and Ω were not really a pair, for o + o became not ω but ου, ο being a close and ω an open sound. In Latin the converse was more nearly true. Though short o changed in the Latin of the last age of the Roman republic to u in unaccented syllables always (except after u whether vowel or consonant), and sometimes also in accented syllables, this was not equally true of -vulgar Latin, as is shown by the Romance languages. In English also the short and the long o are of different qualities, the short in words like not, got being in Sweet’s phonetic terminology a low-back-wide-round, the long in words like no a mid-back-wide-round. The long vowel becomes more rounded as it is being pronounced, so that it ends in a u-sound, though this is not so noticeable in weak syllables like the final syllable of follow. The so-called modified ö is a rounded e-sound found in several varieties. The sound heard in words like the German Giitter is, according to Sweet, a low-front-wide-round, while Jespersen regards it as not low but middle. A mid-front-narrow-round vowel is found short in French words like peu, long in jeûne and in endings like that of honteuse. The Norse sound written φ is of the same nature. (P. Gi.)