It’s known as “The Ineffable Name of God”. Which is a fancy way of saying that you can’t (or at least shouldn’t try to) pronounce it.
It’s also known as the Tetragrammaton, which is Greek for “four-letter word”. Seriously. The four letters correspond roughly to the English letters YHWH. The fact that it doesn’t have any vowels is no great mystery, really: that’s how Hebrew works. They indicate vowels by making little marks next to the consonants… but the Hebrew scriptures left them out for this word, because… you aren’t supposed to pronounce it.
So of course people do.
The Name got passed thru Latin and got corrupted into JHVH, which is where we get the name “Jehovah”. People who understand Hebrew a little better usually say “Yahweh”. But an Orthodox Jew doesn’t say it at all, and says “Adonai” (meaning “lord”) when he gets to that word. The English Bible doesn’t repeat the Name either, instead translating it as “the LORD”. That’s because names hold Power.
No one knows that better than DC Comics’ Captain Marvel. By calling out the name of SHAZAM, he gains the powers of six great heroes of myth: Solomon, Hercules, Atlas, Zeus, Achilles, and Mercury. (Except of course that Solomon is a man from the Bible, not a god or demi-god from Greco-Roman mythology.)
For Captain Miracle, calling out the name of his Patron grants him even greater power. I considered trying to find figures for the letters of YHWH to stand for. But really, what more do you need, when they already spell the Ineffable Name of The One And Only God?