The term 'MUSKETEER's Word' is a three-letter phrase that was popularized by the novel The Three Musketeers by Alexandre Dumas. It is used to describe a code of honor and loyalty among friends, and is often used as a rallying cry for those who stand together in the face of adversity. The crossword solutions for this term are 'ALL', which stands for the phrase 'all for one, one for all'. This phrase encapsulates the idea of solidarity and unity among friends, and is a reminder that everyone should look out for each other.