Gaelic Murchadh "sea-warrior." The Celtic "sea" element is also in names Muriel (q.v.), Murdoch (Old Irish Muireadhach, Old Welsh Mordoc "mariner"), etc. Murphy bed (1925) is named for U.S. inventor William Lawrence Murphy (1876-1959). By happy coincidence, Murphy was an illiterate 18c.-19c. perversion of Morpheus, god of sleep.