Geometry is a branch of mathematics that studies the properties and relationships of shapes, sizes, and figures in space. It involves understanding points, lines, angles, surfaces, and solids. Common geometric shapes include triangles, squares, and circles, each with unique characteristics and formulas for calculating area and perimeter. In addition to basic shapes, geometry also explores more complex concepts like congruence, similarity, and symmetry. It has practical applications in various fields, including architecture, engineering, and computer graphics, helping to design structures and create visual representations of data.