That branch of mathematics which investigates the relations, properties, and measurement of solids, surfaces, lines, and angles; the science which treats of the properties and relations of magnitudes; the science of the relations of space.
Crystals grew inside rock like arithmetic flowers. They lengthened and spread, added plane to plane in an awed and perfect obedience to an absolute geometry that even stones - maybe only the stones - understood. Annie Dillard
You can't criticize geometry. It's never wrong. Paul Rand
It is hard to convince a high-school student that he will encounter a lot of problems more difficult than those of algebra and geometry. E. W. Howe