- Yacht ({{MathWorld | urlname=Yacht | title=Yacht}}): Yacht
- Yahtzee ({{MathWorld | urlname=Yahtzee | title=Yahtzee}}): Yahtzee
- Yanghui Triangle ({{MathWorld | urlname=YanghuiTriangle | title=Yanghui Triangle}}): Yanghui Triangle
- Yang-Mills Connection ({{MathWorld | urlname=Yang-MillsConnection | title=Yang-Mills Connection}}): Yang-Mills Connection
- Yang-Mills Equation ({{MathWorld | urlname=Yang-MillsEquation | title=Yang-Mills Equation}}): Yang-Mills Equation
- Yang-Mills Functional ({{MathWorld | urlname=Yang-MillsFunctional | title=Yang-Mills Functional}}): Yang-Mills Functional
- y-Axis ({{MathWorld | urlname=y-Axis | title=y-Axis}}): y-Axis
- Yff Center of Congruence ({{MathWorld | urlname=YffCenterofCongruence | title=Yff Center of Congruence}}): Yff Center of Congruence
- Yff Central Circle ({{MathWorld | urlname=YffCentralCircle | title=Yff Central Circle}}): Yff Central Circle
- Yff Central Triangle ({{MathWorld | urlname=YffCentralTriangle | title=Yff Central Triangle}}): Yff Central Triangle
- Yff Circles ({{MathWorld | urlname=YffCircles | title=Yff Circles}}): Yff Circles
- Yff Circles Triangles ({{MathWorld | urlname=YffCirclesTriangles | title=Yff Circles Triangles}}): Yff Circles Triangles
- Yff Conjecture ({{MathWorld | urlname=YffConjecture | title=Yff Conjecture}}): Yff Conjecture
- Yff Contact Circle ({{MathWorld | urlname=YffContactCircle | title=Yff Contact Circle}}): Yff Contact Circle
- Yff Contact Triangle ({{MathWorld | urlname=YffContactTriangle | title=Yff Contact Triangle}}): Yff Contact Triangle
- Yff Hyperbola ({{MathWorld | urlname=YffHyperbola | title=Yff Hyperbola}}): Yff Hyperbola
- Yff Parabola ({{MathWorld | urlname=YffParabola | title=Yff Parabola}}): Yff Parabola
- Yff Parabolic Point ({{MathWorld | urlname=YffParabolicPoint | title=Yff Parabolic Point}}): Yff Parabolic Point
- Yff Points ({{MathWorld | urlname=YffPoints | title=Yff Points}}): Yff Points
- Yff's Inequality ({{MathWorld | urlname=YffsInequality | title=Yff's Inequality}}): Yff's Inequality
- Yff Triangles ({{MathWorld | urlname=YffTriangles | title=Yff Triangles}}): Yff Triangles
- y-Intercept ({{MathWorld | urlname=y-Intercept | title=y-Intercept}}): y-Intercept
- Yin-Yang ({{MathWorld | urlname=Yin-Yang | title=Yin-Yang}}): Yin-Yang
- Yiu Circle ({{MathWorld | urlname=YiuCircle | title=Yiu Circle}}): Yiu Circle
- Yiu Circles ({{MathWorld | urlname=YiuCircles | title=Yiu Circles}}): Yiu Circles
- Yiu Triangle ({{MathWorld | urlname=YiuTriangle | title=Yiu Triangle}}): Yiu Triangle
- Young Diagram ({{MathWorld | urlname=YoungDiagram | title=Young Diagram}}): Young Diagram
- Young Girl-Old Woman I... ({{MathWorld | urlname=YoungGirl-OldWomanIllusion | title=Young Girl-Old Woman I...}}): Young Girl-Old Woman I...
- Young's Inequality ({{MathWorld | urlname=YoungsInequality | title=Young's Inequality}}): Young's Inequality
- Young's Integral ({{MathWorld | urlname=YoungsIntegral | title=Young's Integral}}): Young's Integral
- Young's Lattice ({{MathWorld | urlname=YoungsLattice | title=Young's Lattice}}): Young's Lattice
- Young Tableau ({{MathWorld | urlname=YoungTableau | title=Young Tableau}}): Young Tableau
