More info about the name "Lillian"
Lillian is most likely a variant of Lily. Lily originates in Latin and it is derived from the name of a popular flowering plant, a symbol of purity. As a feminine given name it has increased its popularity within the 20th century and nowadays belongs to the 100 top names in the United States. It was probably popularized by the character of Lily Aldrin in the TV series How I Met Your Mother.