First-order

• Exact first-order ordinary differential equation
• First Order (disambiguation)
• First Order Inductive Learner
• First order Fresnel lens
• First-order abstract syntax
• First-order approximation
• First-order arithmetic
• First-order condition
• First-order desire
• First-order differential equation
• First-order differential operator
• First-order election
• First-order fluid
• First-order function
• First-order hold
• First-order inclusion probability
• First-order language
• First-order linear differential equation
• First-order logic
• First-order non-singular perturbation theory
• First-order partial differential equation
• First-order predicate
• First-order predicate calculus
• First-order query
• First-order reduction
• First-order resolution
• First-order stochastic dominance
• First-order theorem provers
• First-order theory
• First-order transition
• Monadic first-order logic
• Order of accuracy
• Original order
• Rate equation
• Strahler stream order