IHS, following the global and religious trend, is an abbreviation of the Greek name for Christ: Yesu/Jesu (pronounced Yeshu in English). Let’s see if this abbreviation is Biblical or made up.

What does ΙΗΣΟΥΣ mean?

In Greek, the name Yeshu is: ΙΗΣΟΥ-Σ and Iēsou-s.
Let me remind you that the root of the name Christ in Greek is: Jesu/Yesu. The forms: Yesus-s and Yesu-n are variations of the name.
Let’s give an example.
In English, the name Thomas is declined and diminutive to: Tommy, Timmy, Timothy, etc. However, the basic form of the name is: Thomas. If someone wants to translate the name Thomas to other languages, they will not take the form: Tommy or Timmy, but the basic form: Thomas.

The same is true with the name of Christ. We do not translate the Greek form of the name to Polish: Yesu-s or Yesu-n, only the basic form: Jesu/Yesu.
So, the first three letters of this name in Greek are: ΙΗΣ (i.e.: iota – eta – sigma).
In the Latin alphabet, they wrote it as: IHS (also as IHC, because the Greek sigma was written as „C”).
Over time, this abbreviation began to be assigned, for example: Iesus Hominum Salvator – Yesu-s, The Savior of people.

How IHS came to be from ΙΗΣΟΥΣ

In the New Testament, the name „Yesu-s” is written as: ΙΗΣΟΥ-Σ and Iēsou-s.
ΙΗΣΟΥΣ are the capital letters of the name Christ, something like „YESHU-s” in English.
Ἰησοῦ are the lowercase letters of the name, i.e. Yeshu/Yesu.

Capital letters (ΙΗΣΟΥΣ)	Lowercase letters (Ἰησοῦ)	Letter name	Pronunciation in English
Ι	Ἰ	iota	y
Η	η	eta	e
Σ	σ	sigma	sh
Ο	ο	omikron	–
Υ	ῦ	upsilon	u
Σ	—	—	(s)

This is the correct abbreviation of the name ΙΗΣΟΥΣ:
• Ι (iota) = „I/Y”
• Η (eta) = „E”.
• Σ (sigma) = „S”
In the Middle Ages, copyists who copied the letters probably didn’t know Greek well, or they made a deliberate mistake.
This is how they did it:
• Ι → I/Y(ok, that’s right).
• Η → H (there’s a mistake here – the Greek eta looks like the Latin „H”, so it was considered „h”, and it should be „e”).
• Σ → S (sigma looks like „C”, but the correct form „S” was adopted. They didn’t make a mistake here…).

From the first letters of the name of Christ: ΙΗΣ they made the Latin: IHS, and from the Greek: ΙΗΣ they should have made the Latin: IES/YES. In this form the abbreviation of the name is correct. They also made a mistake by transferring the Greek name of Christ: Jesu to the English: jesus.It is not known whether they made these mistakes on purpose or by accident. However, if they did it by accident, someone would have changed it to the correct form. They have not done so to this day. Why?

Summary of the Abbreviation IHS

There is no abbreviation in the New Testament: IHS. This abbreviation was created by incorrectly transcribing Greek letters into Latin.
Therefore, IHS does not come from the name of Christ: Yeshu/Yesu.
The greater meaning of the abbreviation IHS is the expression: Iesus Hominum Salvator.
It means: Yeshu/Yesu – Savior of people or Yeshu – Savior of the human race.

Was this written on the cross: INRI?

The abbreviation INRI comes from the Latin inscription that, according to the Gospel, was placed above the head of Christ on the cross. It is an abbreviation of:
• Iesus Nazarenus Rex Iudaeorum, or: Yesu-s the Nazarene, King of the Judeans.

„Pilate also had a notice prepared and fastened to the cross. It read: Yesu-s of Nazareth, the King of the Judeans.” — John 19:19

The inscription is in three languages:

Language	Content of inscription
Hebrew	ישוע הנצרי מלך היהודים
Greek	Ἰησοῦς ὁ Ναζωραῖος ὁ Βασιλεὺς τῶν Ἰουδαίων
Latin	Iesus Nazarenus Rex Iudaeorum – (INRI)

There was no abbreviation on the cross: INRI. According to the above verse, there was a full name:
• Iesus Nazarenus Rex Iudaeorum, or: Yesu-s the Nazarene, King of the Judeans.
Why is the name of Christ in this inscription: Jesus/Yesus?
Because names in Greek are declined. That is why the form from the nominative case was taken:

Case	Greek Form	Transliteration	Pronunciation(English: Yeshu)	Meaning / use case
Nominative (who? what?)	Ἰησοῦ-ς	Iēsou-s	Yesu-s	As the subject of a sentence eg. „Yeshu said…”
Genitive (who? what?)	Ἰησοῦ	Iēsou	Yesu	eg. „disciples of Yeshu”, „name of Yeshu”
Viewfinder (whom? why?)	Ἰησοῦ	Iēsou	Yesu	eg. „he appeared to Yeshu”
Accusative (whom? what?)	Ἰησοῦ-ν	Iēsou-n	Yesu-n	eg. “they saw Yeshu”
Vocative (oh!)	Ἰησοῦ	Iēsou	Yesu	eg. „Yeshu, the Son of David!”