Many people who read the T'nach (Jewish bible) only in translation think that G-d has "a" name. They usually think that His name is comprised of four Hebrew letters. This name is sometimes called tetragrammaton. Over the years people have taken the four Hebrew letters (non-Jewish people) and tried to make up vowel sounds for it. One of the earliest iterations was "Jehovah" -- a very strange pronunciation indeed since Hebrew has no words with a "j" sound!
In reality G-d has many "names," not just one. His holiest name, the tetragrammaton or "four letter" name was never to be spoken outside of prayer, and those prayers where this holiest of name was used was only in the holiest of places -- first the מִשְׁכַּן / Mishkan / Tabernacle (portable Temple) and later in the Temples in Jerusalem (the "j" is an Anglicized pronunciation for יְרוּשָׁלַיִם / Y'rushalayim.
How do we know that His holiest name is not to be said except in these holiest of places? “Whoever utters the (four letter holiest) Name (Tetragrammaton) must be put to death—the entire congregation has to take part in his execution; the same applies to a foreigner as to a citizen: he must die for his uttering of the Name” (Vayikra / Leviticus 24:16).
The Talmud (Gemara, Sh'vuot 35a) lists nine specific names (really descriptions or titles) for G-d that “may not be erased”, and eleven names / descriptions for G-d may “be erased." The mere utterance of the Tetragrammaton is explicitly prohibited in the Torah. And make no mistake, it is explicitly prohibited in the Torah, this isn’t just “an invention of the Rabbis.
Why does G-d have so many names?
Why do Jews not use any of His names outside of prayer?
Even in translations it is easy to see that in the bible names are not just labels. Names have meanings. G-d changes Jacob's name to "Israel." "Your name will no longer be said to be Jacob, but Israel (Yisra'el). You have become great (sar) before G-d and man." Br'eshit / Genesis 32:29. The "j" again as an Anglicized version of his Hebrew name which is יַעֲקֹב / Yaakov. There is no "j" sound in Hebrew.
However, G-d also says: "G-d said to him, 'Your name is Jacob. But your name will not be only Jacob; you will also have Israel as a name.' [G-d thus] named him Israel." Br'eshit / Genesis 35:10.
This means that at times Abraham's son will be called Jacob and at other times Israel.
Bahya ben Asher put it this way. "we may detect a distinct pattern in the Torah sometimes choosing to refer to Jacob by his original name and sometimes by his additional name. The name Jacob applies to the physical part of Yaakov’s personality, matters connected to his terrestrial existence, whereas the name Israel refers to spiritual aspects of his personality, matters connected to his eternal existence in celestial regions.”
Names are not merely "labels" -- they have meaning.
Which brings us back to the topic: G-d has many names in the bible.
Kabbalah (Jewish mysticism) speaks of 72 names for G-d.
Yet, not one of them is really a name.
G‑d has no name. He is infinite and does not have a name -- or a title or a description for that matter. You could say that by definition, G-d has no definition.
What we call His name(s) are simply our attempt at describing the indescribable.
The terms we most often associate with Him from the T'nach are אֱלֹהִים / elohim, a word used to speak not only of G-d but of false gods, angels and even powerful humans in the bible. The word אֱלֹהִים / elohim really translates to "powerful judge" and it describes an entity in a position of authority and power, such as a ruler. This is why G-d tells Moses that He will make Moses an אֱלֹהִים / elohim (powerful ruler) to Pharaoh. . . When we use this term to speak of G-d we are referring to His majesty and His position as our ultimate ruler.
The other common term associated with G-d is אֲדֹ-נָי / Adonai. The Hebrew word אָדוֹן / adon is a masculine noun (all nouns in Hebrew are either masculine or feminine) meaning a lord or master. אֲדֹ-נָי / Adonai is used to speak of G-d as a merciful master. When the tetragrammaton (four letter name for G-d) appears in prayer or in the T'nach we verbally say אֲדֹ-נָי / Adonai. The dashes are not found in the word, I am using them here to avoid spelling the name outside of prayer. . .
אֲדֹ-נָי / Adonai is only used to speak of G-d, but similar words such as אָדוֹן / adon and אֲדֹנִי / adoni which is singular and has the possessive suffix “my” (my master) and אֲדֹנַי / adonai is used to speak of some men and it means "Gentlemen!"
Again, we use these descriptions of G-d only in prayer. Outside of prayer we refer to G-d as הַשֵּׁם / HaShem (The Name) out of respect. In D'varim / Deuteronomy 28:58 we are told "fear this glorious and awesome הַשֵּׁם / HaShem / the name, the L-rd, your G-d,"
Using the term הַשֵּׁם / HaShem (The Name) is a way of referring to G-d with respect as it is not a holy name / description. It is the name of a name. . . Think of הַשֵּׁם / HaShem (The Name) as a place holder -- a way of referring to G-d without accidentally defaming one of His holy names in every day speech.