Wikipedia says, "The term glass developed in the late Roman Empire. It was in the Roman glassmaking center at Trier, now in modern Germany, that the late-Latin term glesum originated, probably from a Germanic word for a transparent, lustrous substance."
But another entry in Wiki reads, "Indigenous development of glass technology in South Asia may have begun in 1730 BCE.Evidence of this culture includes a red-brown glass bead along with a hoard of beads dating to that period, making it the earliest attested glass from the Indus Valley locations. Glass discovered from later sites dating from 600–300 BCE displays common color."
Now the timeline of the Roman Empire is stated as between 27 BC and 476 AD. Clearly, the Indus Valley precedes the Roman empire. So glass must have been known to the Indian subcontinent much earlier than the Roman empire.
So could the word 'glass' have originated from India? Why not?
Here's my theory: There's a sanskrit word called 'Kelasa' which means 'crystal'. Incidentally, 'Kelasa' is the root word for Kailash. Mount Kailash is often referred to as the Crystal Mountain for being pure and sacred. Now doesn't 'kelasa' sound very similar to 'glass'? The red crystal beads that Wiki talks about would have been called the kelasa beads in ancient times. So may be with time, the 'kla' in kelasa became 'gla' and that's how we got glass.