To find a Latin word in an English edition of the Old Testament of the Bible is an anomaly, to say the least. We would expect to find two things in an English edition of the Hebrew Old Testament:
- English translations of essentially any Hebrew part of speech except proper nouns (names), including but not limited to adjectives, adverbs, common nouns, pronouns, and verbs; but,
- English transliterations of Hebrew proper nouns (names)
The Hebrew text of Isa. 14:12 according to the Westminster Leningrad Codex (WLC) reads:
אֵ֛יךְ נָפַ֥לְתָּ מִשָּׁמַ֖יִם הֵילֵ֣ל בֶּן־שָׁ֑חַר נִגְדַּ֣עְתָּ לָאָ֔רֶץ חֹולֵ֖שׁ עַל־גֹּויִֽם׃
Here is a view of Isa. 14:12 in the Aleppo Codex:

The 1611 edition of the King James Version translated the Hebrew text of Isa. 14:12 into English as follows:

How art thou fallen from heaven, O *Lucifer, sonne of the morning: how art thou cut downe to the ground, which didst weaken the nations:
*sidenote: Or, a day-starre.
Here is a table that demonstrates the relationship between the Hebrew text and the 1611 KJV (i.e., interlinear):
Masoretic |
KJV, 1611 |
אֵ֛יךְ |
How |
נָפַ֥לְתָּ |
art thou fallen |
מִשָּׁמַ֖יִם |
from heaven |
הֵילֵ֣ל |
O Lucifer |
בֶּן־שָׁ֑חַר |
sonne of the morning |
נִגְדַּ֣עְתָּ |
how are thou cut downe |
לָאָ֔רֶץ |
to the ground |
חוֹלֵ֖שׁ |
which didst weaken |
עַל־גּוֹיִֽם |
the nations |
Thus, the Hebrew word הֵילֵ֣ל was considered to be a proper noun (a name). But, instead of being transliterated into English as Heilel, it was actually translated into Latin as lucifer, and then that word was written as a proper noun (name) by capitalization of its initial letter, i.e. Lucifer.
Lucifer is a Latin word, not a Hebrew word. It is formed from the Latin suffix -fer, meaning “bearing” or “bearer”,1 joined to the root luc-/lux- meaning “light”. It means “light-bearer” or “light-bearing”. It should not occur in the King James Version English translation of the Old Testament since the Old Testament was originally written in Hebrew, not Latin. So, either הֵילֵל should have been translated into English as “light-bearer” (if it is a common noun) or transliterated as Heilel (if it is a proper noun), but certainly not Lucifer.
If it is a common noun, does הֵילֵל translate into English as “light-bearer” or into Latin as lucifer?
Some might believe that. St. Jerome thought so. After all, when he produced the Vulgate, the Latin translation of the Hebrew Old Testament, he translated הֵילֵל into Latin as lucifer. And, it’s because of St. Jerome and his Vulgate that lucifer ultimately ended up in the KJV. Well, that answers that question, doesn’t it? Not so fast.
It is true that St. Jerome translated הֵילֵל into Latin as lucifer, but in his commentary on Isa. 14:12, he confesses that הֵילֵל meant something else entirely. He wrote,

Noteworthy is the following passage:
in Hebraico, ut verbum exprimamus ad verbum, legitur: Quomodo cecidisti de cælo, ulula fili diluculi.
which translates into English as,
In Hebrew, so that we may express it word-for-word, it is read, “How have you fallen from heaven! Howl, son of the dawn”!
St. Jerome himself confesses that the Hebrew phrase הֵילֵל בֶּן שָׁחַר translates word-for-word (verbum ad verbum) into Latin as ulula fili diluculi, which itself translates into English as “Howl, son of the dawn”! And, again, it was St. Jerome who wrote lucifer in the Vulgate. But, he admits that lucifer doesn’t express the literal meaning of the Hebrew word הֵילֵל. Ulula does.
Why did St. Jerome state that הֵילֵל translates into Latin literally as ulula?
Most are not aware that the Hebrew word הֵילֵל is not actually a hapax legomenon (i.e., a word that only occurs once in the Bible). It actually occurs twice elsewhere:
- Zech. 11:2
הֵילֵ֤ל בְּרֹושׁ֙ כִּֽי־נָ֣פַל אֶ֔רֶז אֲשֶׁ֥ר אַדִּרִ֖ים שֻׁדָּ֑דוּ הֵילִ֨ילוּ֙ אַלֹּונֵ֣י בָשָׁ֔ן כִּ֥י יָרַ֖ד יַ֥עַר הַבָּצִיר WLC
Howl, fir tree; for the cedar is fallen; because the mighty are spoiled: howl, O ye oaks of Bashan; for the forest of the vintage is come down. KJV, 1769
ulula abies quia cecidit cedrus quoniam magnifici vastati sunt ululate quercus Basan quoniam succisus est saltus munitus Vul
- Eze. 21:12 (21:17 Masoretic)
זְעַ֤ק וְהֵילֵל֙ בֶּן־אָדָ֔ם כִּי־הִיא֙ הָיתָ֣ה בְעַמִּ֔י הִ֖יא בְּכָל־נְשִׂיאֵ֣י יִשְׂרָאֵ֑ל מְגוּרֵ֤י אֶל־חֶ֨רֶב֙ הָי֣וּ אֶת־עַמִּ֔י לָכֵ֖ן סְפֹ֥ק אֶל־יָרֵֽךְ׃ WLC
Cry and howl, son of man: for it shall be upon my people, it shall be upon all the princes of Israel: terrors by reason of the sword shall be upon my people: smite therefore upon thy thigh. KJV, 1769
clama et ulula fili hominis quia hic factus est in populo meo hic in cunctis ducibus Israhel qui fugerant gladio traditi sunt cum populo meo idcirco plaude super femur Vul
Not only does the Hebrew word הֵילֵל occur in both verses, but St. Jerome also translated each occurrence into Latin by the imperative ulula, meaning “Howl”! (from the lemma ululo). And, it was ulula (“Howl”!) that St. Jerome confessed was the literal translation of the Hebrew word הֵילֵל in his commentary on Isa. 14:12. What more needs to be said?
Is there any other support besides St. Jerome’s own confession?
Indeed there is. Aquila, who translated the Hebrew Old Testament into Greek in the early 2nd century A.D. (he died ~132 A.D.), translated the Hebrew phrase הֵילֵל בֶּן שָׁחַר into Greek by the phrase ὀλολύζων υἱὸς ὄρθρου, which translates into English as “O‘ wailing one, son of the dawn”. The Greek word ὀλολύζων is a present participle conjugated from the lemma ὀλολύζω.

While Aquila did not translate הֵילֵל as an imperative like Jerome (Latin ulula), he still understood it to be conjugated from the root יל"ל, meaning “Howl”.
In summary, if indeed הֵילֵל was a proper noun referring to the name of an entity, it should have been transliterated into English, which would have produced the word Heilel (or perhaps Helel) in the King James Version. On the other hand, if we are to appreciate its other two occurrences in scripture, we should understand it to be an imperative conjugated from the root יל"ל, meaning “Howl”! The onus is really on those who insist it is a proper name, or even a noun meaning “light-bearer”, to prove why that is so especially in light of its other two occurrences in the books of the prophets Ezekiel and Zechariah.2
Footnotes
1 Many other Latin words with the same suffix -fer may be examined [here] using the Perseus search tool.
2 An argument based on cantillation marks does not seem sufficient for Christian expositors. Consider how the cantillation marks of Isa. 40:3 in the Masoretic text oppose the common Christian translation of Isa. 40:3. We should understand that cantillation marks did not exist until, perhaps, the 9th-10th century A.D. They are in fact a tradition.
References
Field, Frederick. Origenis Hexaplorum. Vol. 2. Oxonii: E Typographeo Clarendoniano, 1875. (456)
Jerome (Hieronymus). “Commentary on the Prophet Isaiah” (Commentaria in Isaiam Prophetam.). Book 5. Patrologiæ Cursus Completus: Series Latina. Ed. Migne, Jacques Paul. Vol. 24. Petit-Montrouge: Imprimerie Catholique, 1865. (165-167)