From Latin 'insula' (island) — meaning both 'of an island' and figuratively 'narrow-minded or isolated in outlook.'
Of or relating to an island; ignorant of or uninterested in cultures, ideas, or peoples outside one's own experience; narrow-minded.
From Late Latin 'insulāris' (of or belonging to an island), from Latin 'insula' (island). The etymology of Latin 'insula' itself has been debated: the most widely accepted analysis connects it to 'in salō' (in the open sea), where 'salum' (the open sea, from PIE *sal-, salt, saltwater) describes the water surrounding an island. This gives 'insula' the sense of a thing surrounded by salt
The phrase 'insular script' refers to the distinctive handwriting style developed in the monasteries of Ireland and Britain during the early Middle Ages. Cut off from continental Europe after the fall of Rome, Irish and British monks developed their own writing traditions on their islands — a literal case of insularity producing something culturally distinctive rather than merely provincial.