The crossword solution for the term 'Negative Joiner' is NOR, which is a three-letter word. NOR is a logical operator that is used to join two statements or terms in a logical expression. It is a type of logical disjunction, meaning it is used to express the idea that one statement or term is false or that both statements or terms are false. In other words, NOR is a negative joining operator that expresses the idea that neither statement or term is true.