From an Old English female personal name Mildþrӯð, derived from mild ‘gentle’ + þrӯð ‘strength’. This was the name of a 7th-century abbess, who had a less famous but equally saintly elder sister called Mildburh and a younger sister called Mildgӯð; all were daughters of a certain Queen Ermenburh. Their names illustrate clearly the Old English pattern of combining and recombining the same small group of name elements within a single family. This name was in fairly regular localized use until the early 18th century and it enjoyed a strong revival throughout England in the 19th century. Its use declined from the 1930s onwards.
English: from Old French bas(se) ‘low’, ‘short’ (Latin bassus ‘thickset’; see Basso), either a descriptive nickname for a short person or a status name meaning ‘of humble origin’, not necessarily with derogatory connotations.