Judeo-Spanish short form of Mirian and Judeo-Catalan short form of Miriam. In some cases it might also be a direct adoption of Judeo-Spanish mira "myrrh" (compare Spanish mirra) or an adoption of the popular Catalan feminine Mira, meaning "notable".
From 美(mi) meaning "beautiful, beauty" or 彌(mi) meaning "spread, fill" combined with 羅(ra) meaning "silk, display". Other hanja combinations are possible.