Valuable Strings is a term used to describe the strings of a musical instrument, such as a violin or guitar. The three crossword solutions for this term are AMATIS (6 letters), STRAD (5 letters), and STRADS (6 letters). Amatis is a type of string made from a synthetic material, while STRAD and Strads are both types of strings made from animal gut. STRAD is a single string, while Strads are multiple strings. All three types of strings are considered valuable due to their superior sound quality and durability.