Question

History of the radical symbol?

Answer 1

The word is of latin origin "radix"

Answer 2

The history of the radical sign is instructive. Following Leonardo Pisano (Leonardo da Pisa) (1220), and up to the 17th century, the symbol R R (from the Latin "radix", i.e. root) was widely employed for "square root" . ... By 1525 one can already find the symbol (Ch. Rudolff, sometimes written as K. Rudolff).