1. The branch of mathematics that deals with points, lines, surfaces, and solids, and examines their properties: Geometry is a subject taught in school which is concerned with the features and relationships of points, lines, angles, curves, surfaces, and solids.
2. In nuclear medicine, any of the various arrangements between a radioactive source and a detector that affects the accuracy of counting or measurement: Counting geometry is a branch of algebraic geometry which deals with assessing the number of clarifications to geometric problems.