A hotspot is a center of high activity within a larger area of low activity. The term is applied to different things in different areas of study:
In geology, a hotspot is a location on the Earth's surface that has vulcanism for a long period of time. Originally thought to be caused by a narrow stream of hot mantle convecting up from the mantle-core boundary [1] (http://pubs.usgs.gov/publications/text/hotspots). The latest geological evidence is pointing to upper-mantle convection as a cause [2] (http://www.geotimes.org/nov00/hotspot)[3] (http://www.dur.ac.uk/g.r.foulger/Offprints/Yellowstone.pdf).
... Venezuela, Guyana, Suriname and French Guiana. Named after brazilwood[?], a local tree, Brazil is home to both extensive agricultural lands and rain ...