Ancient Greek and Latin letters ultimately go back to a Semitic alphabet. Any meaning of the names and shapes of letters must go back to Proto-Semitic eg Aleph

Ancient Greek and Latin letters ultimately go back to a Semitic alphabet. Any meaning of the names and shapes of letters must go back to Proto-Semitic eg Aleph looked like an oxhead and means ox; Bet (originally) looked like and means House. This is akin to if the first letter of our system were called apple and looked like an apple and produced the short "a" sound; The sound "b" was represented by a letter that looked like and was called banana; etc. Greek (and others) adopted the letter shapes and kept the names (Aleph=>Alpha, Bet=>Beta, Gimel=>Gamma, etc) even though Alpha Beta etc bear no meaning in Ancient Greek outside of the letter name. More importantly Greek (and others) adapted the letter shapes (graphemes) to fit their letter sounds (phonemes). For instance, ancient (and modern) Semitic alphabets do not include vowels. Ancient Greek really needed to write vowels. Semitic used glottal stops that Ancient Greek didn't. So, Ancient Greek took the letters of unused sounds (like Aleph, which was originally not the vowel "a" but a glottal stop not used in Ancient Greek) and attributed a vowel sound to it. After appropriating the breathy sound of Het to the long "A" sound of Eta, and a few other vowels, Greek still needed more. So they invented Omicron and Omega, which are just self-explanatory names of "small (ie short) o" and "big (ie long) O." Likewise Upsilon and Epsilon (psilon in Greek means naked/plain; so "plain uh" and "plain eh") All of this is to say that the meanings attributed to Greek or Roman or Etruscan letter shapes in those respective languages were appointed after the fact. To get at the original meaning of these letter shapes, one must refer to its Semitic origins. If interested, one may read what Theo Vennemann has to say about how the Futhark Runes may reflect a direct adoption of the Semitic alphabet by Germanic peoples rather than the more commonly held belief that Germanic tribes got the alphabet from Greeks, Etruscans and Italians.