originally triangulation applied to locating something by taking bearing from different sites (plotting the direction of the object from different directions should lead to lines crossing at one point)
in research the term is used metaphorically to mean using multiple sources of data to help answer a research question
often the term refers to the use of different kind of data (methodological triangulation), but it could be the same types of data collected at different times, or from different informers
See: Triangulation
