A gamut is anything graduated (i.e. marked at regular intervals) used to measure. A ruler, for example, could be called a gamut. In music a gamut represents all the known musical notes. Finally, gamut can also mean a complete range of something (e.g., a gamut of colors).
ESPN’s online arm runs gamut of live sports offerings (USA Today)
The court’s liberal wing strenuously disagreed, offering its own historical construction that emphasized a gamut of restrictions on firearms… (WSJ)