Glastonbury: A town in Somerset, England, twenty-one miles south of Bristol. Its abbey, founded in Roman times, was refounded under Ine in the Eighth Century. Glastonbury is associated in legend with Joseph of Arimathea, who is said to have visited it, and, in sign of possession, planted his staff, which took root and became the famous Glastonbury thorn that bursts into leaf on Christmas eve. The Isle of Avalon, where King Arthur was buried, is also here.