  The term \(U(o)\) represents the utility of the outcome \(o\)—roughly, how valuable \(o\) is.  Formally, \(U\) is a function that assigns a real number to each of the outcomes. (The units associated with \(U\) are typically called utiles, so that if \(U(o) = 2\), we say that \(o\) is worth 2 utiles.) The greater the utility, the more valuable the outcome.