Non-Euclidean geometry, literally any geometry that is not the same as Euclidean geometry. Although the term is frequently used to refer only to hyperbolic geometry, common usage includes those few geometries (hyperbolic and spherical) that differ from but are very close to Euclidean geometry.
Euclidean and Non-Euclidean Geometry: An Analytic Approach: 9780521276351: Ryan, Patrick J.: Books
Question Corner -- Understanding Projective Geometry
Finding a non-euclidean geometry model - Howard Eves' Geometry - Mathematics Stack Exchange
Introduction to Non-Euclidean Geometry - EscherMath
Non-Euclidean geometry, Definition & Types
Maths - Non-Euclidean Spaces - Martin Baker
definition - What precisely is the difference between Euclidean Geometry, and non-Euclidean Geometry? - Mathematics Stack Exchange
Hippocampal spatial representations exhibit a hyperbolic geometry that expands with experience
Hyperbolic Geometry, Overview & Applications - Lesson
Three geometries – Euclidean, Hyperbolic, Elliptical – The Book of Threes
The Geometric Viewpoint History of Hyperbolic Geometry
Some patterns that we have explored and designed using ideas and
Non-Euclidean geometry - Wikipedia
axioms - Is Non-Euclidean geometry really Non? - Mathematics Stack Exchange
How new geometries reshaped our world