An isotherm is a line of equal or constant temperature on a graph, plot, or map; an isopleth of temperature. For example, isotherms are commonly seen on weather maps to show large-scale temperature distributions.
Drawing Contour Plots (http://avc.comm.nsdlib.org/cgi-bin/wiki_print.pl?Drawing_Contour_Plots). A lesson plan that deals with drawing various isopleths including isotherms.
... first to have the title of "Tyrant" was Pisistratus in 560 BC.
In modern times Tyrant has come to mean a dictator who rules with cruelty.
Bullying is a form of ...