Phoenician ayin — "eye", through Greek omicron.
O
ayin means eye, and the earliest Proto-Sinaitic form is a circle with a pupil inside. The dot was gone before the Greeks ever saw it: classical Phoenician ayin is already a plain circle. That is why the Phoenician, Greek and Latin circles are the same drawing — nothing was lost in transit, it was lost earlier.
Anderson · Armstrong · Arnold · Boer · Boyd · Boyer · Brook · Brooks · Brown · Cameron · Carroll · Castillo · Coleman · Collins
In the modern alphabet this letter is number 15 of 26. Before it comes N, after it P. The order itself is inherited: Latin took it from Greek, Greek from Phoenician, and the sequence has survived largely unchanged for about three thousand years. Every rearrangement since has been an insertion, not a reshuffle.
This is a vowel: the syllable rests on it, and vowels set the rhythm of a name. In a corpus of 315 surnames this letter opens 5 and closes 12. Among the 96 given names in the base it appears in 26. The surname carrying the most of it is Colombo, with 3.
John · Robert · Joseph · Thomas · Christopher · Anthony · George · Timothy · Jacob · Nicholas · Noah · Oliver
These letters came from the Greek alphabet.