Susi is of Latin origin, derived from the Roman family name Susius, which is believed to be an ancient Sabine name meaning 'lily'. The name gained popularity in Germany during the Middle Ages and has since been widely used throughout Europe. In some cultures, Susi is considered a diminutive of names like Susanne or Susan, while in others, it stands independently as a given name.
"The name Susi experienced a significant peak in popularity during the late 1950s to early 1960s, with 24 births recorded in 1959 and 22 in 1960. However, it seems the trend declined thereafter, with most years showing fewer than 15 births per year since the 1970s. The total number of births for the name Susi over this period is 392."