- 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.
- Maskerade (Wikipedia)
Maskerade is a fantasy novel by British writer Terry Pratchett, the eighteenth book in the Discworld series. The witches Granny Weatherwax and Nanny Ogg visit the Ankh-Morpork Opera House to find Agnes Nitt, a girl from Lancre, and get caught up in a story similar to The Phantom of the Opera.