An expression of teamwork, used when there are two people on a team, in any kind of event, against two or more people. Originates from the xbox 360 console game Army Of Two, where there are certain "Back To Back" sequences. Of these sequences, both characters return to back and begin shooting, being effortlessly dispatch their particular enemies, who will be frequently terrorists. At these times, sometimes among the characters, Tyson Rios, shouts "back-to-back, Salem!", Salem being the past name for the other personality. This term can be utilized anytime to imply teamwork.