Formulas
- Action at a distance
- Activated complex
- Activation energy
- Activity coefficient
- Acyclic orientation
- Adaptive Simpson's method
- Category of elements
- Catenary
- Cauchy's integral formula
- Cauchy surface
- Cauchy–Schwarz inequality
- Causality
- Cayley–Hamilton theorem
- Cederbaum's maximum flow theorem
- Center (group theory)