The term 'IS OF SERVICE' can be broken down into two crossword solutions: AIDS (4 letters) and OF SERVICE (9 letters). AIDS stands for Acquired Immunodeficiency Syndrome, which is a serious, life-threatening condition caused by the human immunodeficiency virus (HIV). OF SERVICE refers to providing assistance or support to someone or something. Together, the phrase 'IS OF SERVICE' implies that someone is providing help or support to those affected by AIDS.