One can make a color-color plot by arranging stars in a two-dimensional graph, where each axis measures a different color index. Below are some examples from the SDSS, which uses a set of broadband filters called (u, g, r, i, z); they are very roughly equivalent to (U, B, R, I, _).
regime - the organization that is the governing authority of a political unit; the government reduced taxes; the matter was referred to higher authorities. authorities, government.
Full Definition of TYRANT. 1. a: an absolute ruler unrestrained by law or constitution b: a usurper of sovereignty. 2. a: a ruler who exercises absolute power oppressively or brutally b: one resembling an oppressive ruler in the harsh use of authority or power. See tyrant defined for English-language learners.