Triple means multiplying by three. It is important to note that with regard to some other terms and concepts like vectors and triple product this does not always hold true. For instance, with triple product triple means that three vectors are used, not that anything is multiplied by a factor of three. Triple can also represent a group of three elements, also referred to as a triad. A triple in this case is therefore a 3-tuple.
“Triple.” From Wolfram MathWorld, mathworld.wolfram.com/Triple.html.