🔼The name Silla in the Bible
It's not entirely sure whether Silla is a Biblical name or not, but the authors of all modern English translations appear to suppose so and so did those who produced the Septuagint and the Vulgate. So what's the big screaming deal?
The troubling passage appears in 2 Kings 12:20, where Jozabad (or Zabad, according to 2 Chronicles 24:26) and Jehozabad murder king Joash. The Chronicler informs us that Joash died in his bed, and the author of Second Kings reveals that the murder took place at or in the royal complex at Millo near Jerusalem. The two words that follow the word Millo (namely היורד סלא) describe a downward motion towards silla. The question is: what's moving?
If Joash is moving (from the royal complex at Millo to a proposed but otherwise unknown location named Silla), then he wasn't murdered in his bed but on the road. And why would the author of Kings refer to a place that's otherwise entirely unknown? Saying that Joash was murdered on the way from Millo to Silla is like saying that Kennedy was shot on the road from Dealey Plaza to Langford Street.
And so a small group of theologians (among whom the renowned Gesenius) proposed that our word silla is not the name of a location but an otherwise unused noun meaning highway, drawn from the verb סלל (salal; see below). Allowing for that would put Millo by a descending highway (and descending in this sense means perpendicular to Jerusalem), and Joash sound asleep in his royal pad.
The obvious downside of this proposal is that it doesn't explain why the well-known complex of Millo would need an additional reference to the highway out of Jerusalem.
🔼Etymology of the name Silla
The origin of the word or name Silla should probably be traced to the following root-group:
For a meaning of the name Silla, NOBSE Study Bible Name List reads Twig, Basket (and deems Silla a quarter or suburb of Jerusalem). Jones' Dictionary of Old Testament Proper Names calls Silla a town near to Jerusalem and translates its name with Heap Of Earth or Highway. BDB Theological Dictionary does not try to interpret our name.