Where does “má” come from?

má (Irish) comes from Old Irish má, from Old Irish ís, from Proto-Celtic ɸīssu, from Proto-Indo-European pedsú, from Proto-Indo-European pṓds, from Proto-Indo-European póds, from Proto-Indo-European ped- — to walk, to step; to stumble, to fall.

má (Irish): plain expanse of land with relatively low relief, champaign open countryside, or an area of open countryside