- proper point of inflection
- proper polynomial
- proper product
- proper property
- proper quadric
- proper quadric curve
- proper quadric surface
- proper quasi-rotation
- proper quotient object
- proper rational function
- proper refinement
- proper Reinhardt domain
- proper representation
- proper right divisor
- proper rotation
- proper rotation group
- proper segment
- proper sigma-ideal
- proper similarity
- proper solution
- proper space
- proper sphere
- proper spiral point
- proper subalgebra
- proper subcategory