🔼The name Eglath-shelishiyah in the Bible
The name Eglath-shelishiyah occurs twice in the Bible. It's the name of a city near Zoar in Moab and both Isaiah and Jeremiah refer to it (Isaiah 15:5, Jeremiah 48:34). For some reason, scholars of old didn't think that Eglath-shelishiyah was a name and endeavored to squeeze the translation of it into the narrative (see the King James, JSP and Young translations).
🔼Etymology of the name Eglath-shelishiyah
The name Eglath-shelishiyah consists of two elements. The first part appears to be an alternate version of the regular noun עגלה (eglah), meaning calf or heifer, from the root עגל ('igl):
The second part of our name comes from the root שלש (shalash), and has to do with the number three:
The final two letters of our name are יה (yah), which might be due to some grammatical construction, except that the word שלשיה does not occur anywhere in Scripture other than in our name. In all other cases, when יה occurs in a name, it's quickly recognized as an abbreviated form of the Tetragrammaton יהוה, YHWH, or Yahweh (see the buttons to the left for more names that either start or end with יה).
For a meaning of the name Eglath-shelishiyah, both NOBSE Study Bible Name List and BDB Theological Dictionary read (The) Third Eglath. Jones' Dictionary of Old Testament Proper Names doesn't treat Eglath-shelishiyah because he works off older translations.
The King James Version, and JSP and Young translations of the Bible all state that Isaiah calls Zoar of Moab a Heifer Of Three Years Old and Jeremiah does the same to Horonaim.
If we regard the final יה as a reference to the Lord, our name becomes Heifer Of Yah's Three, whatever that might mean.