Wallis Sieve
A compact set 
with Area
created by punching a square hole of length
in the center of a square. In each of the eight squares remaining,punch out another hole of length 
, and so on.- Noetherian Ring
- Noether-Lasker Theorem
- Noether's Fundamental Theorem
- Noether's Transformation Theorem
- Noise
- Noise Sphere
- Nolid
- Nome
- n-Omino
- Nomogram
- Nonagon
- Nonagonal Number
- Nonagram
- Nonassociative Algebra
- Nonassociative Product
- Nonaveraging Sequence
- Noncentral Distribution
- Noncommutative Group
- Nonconformal Mapping
- Nonconstructive Proof
- Noncototient
- Noncylindrical Ruled Surface
- Nondecreasing Function
- Nondividing Set
- Nonessential Singularity