Geometry (from Ancient Greek __ γεωμετρία (_geōmetría) 'land
measurement'; from __ γῆ (gê) 'earth, land' and __ μέτρον (métron) 'a
measure') is a branch of mathematics concerned with properties of space such
as the distance, shape, size, and relative position of figures. Geometry is,
along with arithmetic, one of the oldest branches of mathematics. A
mathematician who works in the field of geometry is called a _geometer. Until
the 19th century, geometry was almost exclusively devoted to Euclidean
geometry, which includes the notions of point, line, plane, distance, angle,
surface, and curve, as fundamental concepts.