The term NA AND CL- is an abbreviation for the chemical compound sodium and chloride. Sodium and chloride are two of the most abundant elements in the Earth's crust, and they are essential components of many biological processes. Sodium and chloride ions are also important components of salt, which is used to flavor food and preserve it. The crossword solution for this term is IONS, which stands for ionic compounds. Ionic compounds are formed when positively charged ions, such as sodium and chloride, are attracted to each other and form a lattice structure.