"Orme" is from an old Norse word meaning "serpent" - the Great Orme is a serpentine rock formation sticking out to sea. Rather like the Worm's Head near where we live. The Vikings settled around the coast of Wales, and a lot of place names are Norse rather than Welsh - Swansea was originally "Sweyne's Ey" from an island settlement by a Viking called Sweyn (a common Norse name). Rhossili is pronounced much as it looks - Rossilly - but what would you make of Cwmrhydiceirw?

Andrew