Euclidean Plane
The 2-D Euclidean Space denoted 
.
- Koch Island
- Koch Snowflake
- Koebe Function
- Koebe's Constant
- Kollros' Theorem
- Kolmogorov-Arnold-Moser Theorem
- Kolmogorov Complexity
- Kolmogorov Constant
- Kolmogorov Entropy
- Kolmogorov-Sinai Entropy
- Kolmogorov-Smirnov Test
- Korselt's Criterion
- Kovalevskaya Exponent
- Kozyrev-Grinberg Theory
- k-Partite Graph
- Kramers Rate
- Krawtchouk Polynomial
- Kreisel Conjecture
- Kronecker Decomposition Theorem
- Kronecker Delta
- Kronecker Product
- Kronecker's Polynomial Theorem
- Kronecker Symbol
- Krull Dimension
- Kruskal's Algorithm