Vaccines are a type of medical treatment that helps to protect people from infectious diseases. The term 'vaccines' is derived from the Latin word 'vacca, ' which means cow, and refers to the first vaccine developed by Edward Jenner in 1796. The crossword solution for the term 'vaccines' is SERA, which stands for 'subcutaneous emulsion of rabies antigen.' This is a type of vaccine used to protect against rabies, a virus that can be fatal if left untreated.