Abarim Publications' online Biblical Greek Dictionary
The noun ιωτα (iota) is the name of the ninth letter of the Greek alphabet. Since the Greek alphabet is an adaptation of the Semitic one (and see our article on the name Hellas for more on this), the Greek letter ιωτα (iota) is an adaptation of the Hebrew tenth letter, namely י (yod), which itself was named after the noun יד (yad), meaning fist, which in turn looks like a derivation of the verb ידד (yadad), to love, which obviously relates to the noun דוד (dod), beloved, which is spelled the same as the name David, the proverbially beloved king.
The noun ιωτα (iota) occurs only once in the New Testament, namely in Matthew 5:18, where Jesus states that heaven and earth will pass away before one ιωτα (iota) or one κεραια (keraia) will pass from the law. Commentators commonly assert that these two terms signify the smallest and thus least significant elements of script, but these commentators are clearly not familiar with the story of David and Goliath, or even Jesus' observation that the tiniest seed can contain an entire ecosystem (Matthew 13:32).
Size, rather obviously, does not matter, and the only thing that matters is completeness and wholeness (שלום, shalom, see Matthew 6:33). The ιωτα (iota) and κεραια (keraia) of the Law are not the Law's least significant elements, but instead its two most fundamental building blocks: the self-containing assertion (e.g. God is love), and the command (e.g. love God), which relate like bow and arrow.
The י (yod) was one of three symbols with which the ancients Hebrews noted vowels — the other two were ה (he) and ו (w) — and vowel notation is what completed the alphabet, and the alphabet allowed mass literacy. Through literacy, humanity could roam and explore its past, which in effect created an entire mental dimension that is unique to humans (said slightly more popular: in the world of dogs, there never was an Elvis). That means that vowel notation literally created modern humanity, which explains why the Name of the Creator is formed from only these magic vowel symbols: יהוה (yhwh) or YHWH.
These three symbols also served as consonants, which means that every one of these three symbols can be pronounced as a vowel or as a consonant, depending on the reader's good humor, and that means that the name YHWH can be pronounced in eight different ways (which is why we don't pronounce it in any one way, lest we deny the other 7/8th of the Creature's nature).
Since the yod is the one with which the name of the Lord begins, it somewhat represents this whole Name (on occasion this vast Name, from which sprang the whole universe, appears wholly abbreviated in a single yod). As such it represents the pure state of quantum uncertainty (pure fifty-fifty), as well as binariness, and even the great mystery of why there is existence (versus non-existence), and thus the entire Word of God and hence the nature of God entirely (and please see our article on the verb πασχω, pascho, meaning to experience, for a slower paced look at these difficult concepts).
We have very little actual proof, in an academic sense, but here at Abarim Publications we privately suspect that the two words יד (yad) and קרן (qeren), or ιωτα (iota) and κεραια (keraia), or "fist" and "horn(s)", represented what we moderns call "vowel" and "consonant".