E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Gloucester (2 syl.).
The ancient Britons called the town Caer Glou (bright city). The Romans Latinised Glou or Glove in Glev-um, and added colonia (the Roman colony of Glev-um). The Saxons restored the old British word Glou, and added ceaster, to signify it had been a Roman camp. Hence the word means Glou, the camp city. Geoffrey of Monmouth says, when Arviragus married Genuissa, daughter of Claudius Cæsar, he induced the emperor to build a city on the spot where the nuptials were solemnised; this city was called Caer-Clau, a contraction of Caer-Claud, corrupted into Caer-glou, converted by the Romans into Glou-caster, and by the Saxons into Glou-ceaster or Glou-cester. Some, continues the same philologist, derive the name from the Duke Gloius, a son of Claudius, born in Britain on the very spot.