'Stanmore' means the stony pool.
It comes from Old English stān, stony, and mere, a pool. The name is first documented in a charter of 793, when land here was granted to St Albans Abbey, and the Domesday Book of 1086 records two manors called Stanmere. The stones are probably the gravel outcrops on the clay soil; the pool may have been one of the ponds that still exist.