Lyndall is of Welsh origin, derived from the elements "llwyn" meaning grove and "dy" meaning peace. It is a unisex name but has been more commonly used for females in recent years. Lyndall is also associated with South African literature, as it is the title of a novel by Olive Schreiner published in 1890.
"Lyndall was quite popular as a girl's name in the mid-20th century, peaking between 1958 and 1961 with over 13 to 15 births per year. However, it seems usage dropped off significantly after that period, with fewer than 10 births per year from 1962 onwards."