The term 'Three Musketeers' Word' is a reference to the novel The Three Musketeers by Alexandre Dumas. The crossword solutions for this term are ONE (3 letters) and ALL (3 letters). The phrase 'ONE for All and All for ONE' is a famous quote from the novel, which is a motto of the three musketeers and their friends. This phrase emphasizes the idea of loyalty and friendship, and is a reminder that everyone should look out for each other.