Amicus usque ad aras is a Latin phrase meaning "a friend as far as to the altar" "a life-long partner" “a friend to the very end." The plural of amicus is amici leading to a separate usage of amici usque ad aras.A song of the same name dates to the defunct Yale University greek organization Phi Theta Psi in 1864. The tune used comes from the traditional song Annie Lisle. Phi Kappa Psi fraternity's song "Amici" includes the phrase "amici usque ad aras" and appears to be based on the Yale tune.