Where does the word Glasgow come from?

Glasgow takes its name from the Brittonic Cumbric language word clasgu, meaning "dear green place", or "green hollow", referring to the verdant valley below the Cathures where the pre-Christian settlement was located. The Brittonic name also appears in the annals of Ulster as Glasschu. The name Glaisno came into use in the 12th century but was eventually replaced by Glasgow.