The actual name of the group being al-Dawla al-Islamiya al-Iraq al-Sham in (Islamic State of Iraq and the Levant)
ISI
S, greatest extent

syrian region under multiple arabic caliphates

ottoman province of syria (arabic: al-
sham)

all of these syrias are well-established regions with multiple documented and legally defined boundaries
but clearly this fuzzy blob is a much better region to describe them with:

also:
syria is derived from assyria
here's a map of the assyrian empire at its height

from wikipedia:
"The Levant (/ləˈvænt/; Arabic: المشرق [ʔalmaʃriq])[3] is an approximate historical geographical term referring to a large area in the Eastern Mediterranean. In its narrowest sense it is equivalent to the historical region of Syria. In its widest historical sense, the Levant included all of the eastern Mediterranean with its islands,[4] that is, it included all of the countries along the Eastern Mediterranean shores, extending from Greece to Cyrenaica.[2][5]"
it's a worthless term that only has applications in certain cultural subjects. geographically speaking the levant is little more than a geographic meme
maybe don't be an arrogant twat over semantics
speaking of which:

acronyms
are literally names