（又称“正极限”)- LSE (= least squares estimate)
- l-semigroup
- L-separation theorem
- L-series
- L-series of elliptic curve
- L-shaped method
- L-space
- L-spline
- LST (= longest service time)
- L-structure
- l-subgroup
- l-subring
- L-system
- L-theory
- Lubin, J.
- Lubin-Tate formal group
- lubrication equation
- lubrication theory
- Lucas central circle
- Lucas central triangle
- Lucas chain
- Lucas circles
- Lucas circles radical circle
- Lucas correspondence
- Lucas correspondence theorem