noun: (advertising) Initialism of click-through rate. [(Internet, advertising) A ratio of the number of clicks on a unit of online advertising to the number of times it is shown.]
noun: (finance) Initialism of cash transaction report.
noun: Abbreviation of centre.
noun: (US) Abbreviation of center. [The point in the interior of a circle that is equidistant from all points on the circumference.]