What and who is
Hebrew: תַּרְשִׁישׁ —transliteration: Tarshish
This is a Sanscrit or Aryan word, meaning: “the sea coast”
This was the name of biblical men and a place.
Tarshish, son of Javan
Tarshish, son of Bilhan, a Benjamite
…the sons of Bilhan: Jeush, Benjamin, Ehud, Chenaanah, Zethan, Tarshish, and Ahishahar. —1 Chronicles 7:10
Tarshish, a high-ranking nobleman of Persia
Then the king said to the wise men who knew the times (for this was the king's procedure toward all who were versed in law and judgment, the men next to him being Carshena, Shethar, Admatha, Tarshish, Meres, Marsena, and Memucan, the seven princes of Persia and Media, who saw the king’s face, and sat first in the kingdom)… —Esther 1:14 ESV
Tarshish, a port trading in precious metals
The name of this place first comes to notice in the days of Solomon. The location of Tarshish has been lost to time and has given rise to much discussion. Some think there was a Tarshish in the East, on the Indian coast, seeing that “ships of Tarshish” sailed from Ezion-geber, on the Red Sea (1 Kings 9:26; 22:48; 2 Chronicles 9:21). Some, again, argue that Carthage (Tunis) in northern Africa may be the place. Others suggest it was another name for Sardinia, the 2nd largest island in the Mediterranean Sea.
There can be little doubt, however, that this is the name of a Phoenician port in Spain, between the two mouths of the Guadalquivir (the name given to the river by the Arabs, and meaning “the great wady” or water-course). It was founded by a Carthaginian colony, and was the farthest western harbor of Tyrian sailors. It was to this port Jonah's ship was about to sail from Joppa.
“Ships of Tarshish”
It appears that this name also is used without reference to any locality. “Ships of Tarshish” is an expression sometimes denoting simply ships intended for a long voyage (Isaiah 23:1, 14), ships of a large size (sea-going ships), whatever might be the port to which they sailed. Solomon’s ships were so styled (1 Kings 10:22; 22:49).