- D'Alembert criterion (convergence of series)
- D'Alembert criterion for convergence
- D'Alembert equation
- D'Alembert formula
- D'Alembert operator
- D'Alembert principle
- D'Alembert ratio test
- D'Alembert's equation
- D'Alembert's Solution or D'Alembert's solution
- D'Alembert-Euler conditions
- D'Alembertian
- D-module
- DAG or Dag
- Dagger
- Daisy
- Damascius
- Damped Simple Harmonic Motion or Damped simple harmonic motion
- Dandelin spheres
- Dandelin-Gräffe method
- Daniell integral
- Danielson-Lanczos lemma
- Darboux function
- Darboux Integral or Darboux integral
- Darboux property
- Darboux sum
- Darboux theorem
- Darboux vector
- Darboux's Theorem or Darboux's theorem
- Darboux's theorem (analysis)
- Dart
- Dash
- Data cube
- Data point
- Data stream
- Data structure
- Database
- Daubechies wavelets
- David Eppstein
- David Hilbert or David hilbert
- David Huffman
- Dawson's integral
- Dc
- De Bruijn constant
- De Bruijn diagram
- De Bruijn digraph
- De Bruijn Graph or De Bruijn graph
- De Bruijn sequence
- De Bruijn-Newman constant
- De Finetti theorem
- De Gua's theorem
- De Moivre formula
- De Moivre's formula
- De Moivre's identity
- De Morgan algebra
- De Morgan's laws or De Morgan's Laws
- De Polignac's conjecture
- De Rham cohomology or De rham cohomology
- De Rham theorem
- De Rham-Weil theorem
- De Sitter space or De sitter space
- De Sluze conchoid
- Debye functions
- Debye length
- Decad
- Decade
- Decagon
- Decagonal number
- Decagram
- Decahedron
- Decidable
- Decidable set
- Decile
- Decillion
- Decimal
- Decimal approximation of a real number
- Decimal comma
- Decimal expansion
- Decimal fraction
- Decimal period
- Decimal place
- Decimal point
- Decision problem
- Decision Theory or Decision theory
- Deck transformation
- Declination
- Decoding
- Decomposable
- Decomposable continuum
- Decomposition
- Decomposition group
- Deconvolution
- Decreasing function
- Decreasing sequence
- Dedekind completion
- Dedekind cut
- Dedekind cuts
- Dedekind domain
- Dedekind eta function
- Dedekind eta-function
- Dedekind function
- Dedekind infinite
- Dedekind ring
- Dedekind section
- Dedekind sum
- Dedekind zeta function
- Dedekind zeta-function
- Dedekind-finite
- Deduction
- Deduction theorem
- Deep hole
- Defect
- Defective matrix
- Defective number
- Deficiency
- Deficient number
- Definable
- Definable set
- Defined
- Definite clause
- Definite integral
- Definition
- Deformation
- Deformation retract
- Deformation theory
- Degen's eight-square identity
- Degeneracy
- Degenerate
- Degenerate distribution
- Degenerate matrix
- Degree
- Degree (graph theory)
- Degree matrix
- Degree of a continuous mapping
- Degree of a mapping
- Degree of Freedom or Degree of freedom
- Degrees of freedom
- Dehn invariant
- Dehn lemma
- Dehn surgery
- Dehn's lemma or Dehn's Lemma
- Del
- Del Pezzo surface
- Delaunay Triangulation or Delaunay triangulation
- Delay differential equation
- Delian League or Delian league
- Delian problem
- Delphic oracle
- Delta distribution
- Delta function
- Delta operator
- Delta-function
- Delta-ring
- Deltahedron
- Deltohedron
- Deltoid
- Deltoidal hexecontahedron
- Deltoidal icositetrahedron
- Dempster-Shafer theory
- Dendrite
- Denjoy Integral or Denjoy integral
- Denjoy-Perron integral
- Denominator
- Dense
- Dense set
- Dense-in-itself
- Density
- Density function
- Density matrix
- Density of a probability distribution
- Denumerable Set or Denumerable set
- Denumerably Infinite or Denumerably infinite
- Dependence relation
- Depth
- Depth of a module
- Depth-first search
- Depth-first traversal
- Derangement
- Derivation
- Derivation (abstract algebra)
- Derivation algebra
- Derivative
- Derivative of matrix
- Derivative of Riemann integral
- Derived category
- Derived functor
- Derived group
- Derived set
- Derived subgroup
- Dervish
- Desargues graph
- Desargues' theorem or Desargues' Theorem
- Descartes theorem
- Descartes' rule of signs
- Descending chain condition or Descending Chain Condition
- Descriptive geometry
- Descriptive set theory
- Design
- Design of experiments
- Design theory
- Destructive dilemma
- Det
- Determinant
- Determinant expansion by minors
- Determinant line-bundle
- Determinant of the Vandermonde matrix
- Determinant theorem
- Deterministic
- Deterministic finite state machine
- Deterministic Turing machine
- Developable surface
- Development
- Development (topology)
- Deviance
- Deviation
- Devil's curve
- Devil's pitchfork
- Devil's Staircase or Devil's staircase
- Diabolic square
- Diabolical Cube or Diabolical cube
- Diabolical square
- Diabolo
- Diagonal
- Diagonal functor
- Diagonal intersection
- Diagonal magic cube
- Diagonal matrix or Diagonal Matrix
- Diagonal Slash or Diagonal slash
- Diagonal subgroup
- Diagonalizable
- Diagonalizable matrix
- Diagonalization
- Diagonally dominant matrix
- Diagram
- Diagram chasing
- Dialectic
- Diameter or DIAMETER
- Diamond
- Dianalytic structure
- Dice
- Dichotomy
- Dickson invariant
- Dictionary order
- Dielectric constant
- Diesis
- Diffeomorphic
- Diffeomorphism
- Difference
- Difference equation
- Difference of two sets
- Difference operator
- Difference quotient
- Difference set
- Different
- Differentiable
- Differentiable function
- Differentiable manifold
- Differentiable structure
- Differential
- Differential algebra
- Differential calculus
- Differential entropy
- Differential equation
- Differential evolution
- Differential field
- Differential form
- Differential geometry or Differential Geometry
- Differential graded algebra
- Differential ideal
- Differential k-form
- Differential operator
- Differential ring
- Differential structure
- Differential topology
- Differential-algebraic equation
- Differentiating under the integral sign
- Differentiation
- Differentiation under the integral sign
- Diffie–Hellman key exchange or Diffie–Hellman Key Exchange
- Diffie–Hellman protocol
- Diffusion equation
- Diffusion process
- Digamma function
- Digit
- Digit sum
- Digital root
- Digital tree
- Digon
- Digraph
- Dihedral Angle or Dihedral angle
- Dihedral group
- Dihedral group D2
- Dihedral group D3
- Dihedral group D4
- Dihedral group D5
- Dihedral group D6
- Dihedral group D7
- Dihedral prime
- Dihedron
- Dihedron group
- Dijkstra algorithm
- Dijkstra's Algorithm or Dijkstra's algorithm
- Dilatation
- Dilation
- Dilemma
- Dilogarithm
- Dilworth's theorem
- Dimension
- Dimension (vector space)
- Dimension axiom
- Dimension function
- Dimension theory
- Dimensional analysis
- Dimensionality
- Dimensionless Number or Dimensionless number
- Diminished rhombicosidodecahedron
- Dini derivative
- Dini theorem
- Dini's test
- Dini's theorem
- Diogenes Laertius
- Diophantine analysis
- Diophantine approximation
- Diophantine approximations
- Diophantine equation
- Diophantine equations
- Diophantine geometry
- Diophantine set
- Dipole graph
- Dipyramid
- Dirac algebra
- Dirac delta function
- Dirac delta-function
- Dirac distribution
- Dirac Equation or Dirac equation
- Dirac Matrices or Dirac matrices
- Dirac measure
- Dirac monopole
- Dirac notation
- Dirac operator
- Dirac spinor
- Dirac's Theorem or Dirac's theorem
- Direct image
- Direct image functor
- Direct limit
- Direct product
- Direct product of groups
- Direct product of modules
- Direct proportion
- Direct sum
- Direct sum of Hilbert spaces
- Direct sum of modules
- Direct summand
- Direct system
- Direct variation
- Directed Acyclic Graph or Directed acyclic graph
- Directed graph
- Directed Infinity or Directed infinity
- Directed set
- Direction
- Direction cosine
- Direction cosines
- Direction field
- Direction vector
- Directional derivative
- Directly proportional
- Director
- Directrix
- Dirichlet algebra
- Dirichlet beta function
- Dirichlet boundary conditions
- Dirichlet box principle
- Dirichlet character
- Dirichlet conditions
- Dirichlet convolution
- Dirichlet criterion (convergence of series)
- Dirichlet density
- Dirichlet distribution
- Dirichlet divisor problem
- Dirichlet eta function
- Dirichlet function
- Dirichlet integral
- Dirichlet Integrals or Dirichlet integrals
- Dirichlet kernel
- Dirichlet L-function
- Dirichlet L-series
- Dirichlet Laplacian
- Dirichlet principle
- Dirichlet problem or Dirichlet Problem
- Dirichlet process
- Dirichlet region
- Dirichlet series
- Dirichlet tesselation
- Dirichlet tessellation
- Dirichlet theorem
- Dirichlet's approximation theorem
- Dirichlet's Box Principle or Dirichlet's box principle
- Dirichlet's convergence test
- Dirichlet's principle
- Dirichlet's Test or Dirichlet's test
- Dirichlet's theorem
- Dirichlet's unit theorem
- Disc
- Disc of convergence
- Disconnected graph
- Disconnected set
- Disconnected space
- Discontinuity
- Discontinuous
- Discontinuous action
- Discontinuous function
- Discrepancy
- Discrete category
- Discrete cosine transform or Discrete Cosine Transform
- Discrete distribution
- Discrete Fourier transform or Discrete fourier transform or Discrete Fourier Transform or discrete Fourier transform
- Discrete geometry
- Discrete group
- Discrete group theory
- Discrete lattice
- Discrete Log or Discrete log
- Discrete logarithm or Discrete Logarithm
- Discrete math
- Discrete Mathematics or Discrete mathematics
- Discrete measure
- Discrete metric
- Discrete series
- Discrete series (of representations)
- Discrete series representation
- Discrete set
- Discrete sine transform
- Discrete space
- Discrete subgroup
- Discrete topology
- Discrete Uniform Distribution or Discrete uniform distribution
- Discrete valuation
- Discrete valuation ring
- Discretization method
- Discriminant
- Discriminant analysis
- Discriminant function
- Disdyakis dodecahedron
- Disdyakis triacontahedron
- Disjoint
- Disjoint sets
- Disjoint union
- Disjoint union (topology)
- Disjunct
- Disjunction
- Disjunctive normal form or Disjunctive Normal Form
- Disjunctive sum
- Disjunctive syllogism
- Disk
- Disk algebra
- Disk Covering Problem or Disk covering problem
- Dispersion
- Dispersion equation
- Dispersion point
- Dispersion Relation or Dispersion relation
- Disphenocingulum
- Disphenoid
- Dissection
- Dissection puzzles
- Dissipative operator
- Dissipative system
- Distance
- Distance (graph theory)
- Distance graph
- Distance to a set
- Distance-regular graph
- Distributed computing project
- Distribution
- Distribution (differential geometry)
- Distribution ensemble
- Distribution function
- Distribution of prime numbers
- Distributive
- Distributive lattice
- Distributivity
- Ditrigonal dodecadodecahedron
- Divergence
- Divergence Theorem or Divergence theorem
- Divergent sequence
- Divergent series
- Divide
- Divide and conquer algorithm
- Divided difference
- Divided differences
- Dividend
- Divides
- Divine Proportion or Divine proportion
- Divisibility
- Divisibility in rings
- Divisibility test
- Divisibility tests
- Divisible
- Divisible group
- Divisible module
- Division
- Division (mathematics)
- Division algebra
- Division algorithm for integers
- Division by zero or Division by Zero
- Division ring
- Divisor
- Divisor (algebraic geometry)
- Divisor class group
- Divisor function
- Divisors
- Dixon's factorization method
- Dobinski's formula
- Docent
- Dodecadodecahedron
- Dodecagon
- Dodecahedral conjecture
- Dodecahedron
- Dolbeault cohomology
- Dolbeault operators
- Dom
- Domain
- Domain (in ring theory)
- Domain (mathematics)
- Domain of definition
- Domain of holomorphy
- Dome
- Dominance
- Dominant strategy
- Dominant weight
- Dominated convergence theorem
- Dominating set
- Domination
- Domination number
- Domineering
- Domino
- Donald Knuth
- Donaldson invariant
- Donaldson theory
- Donaldson's theorem
- Donut
- Door space
- Doppler effect
- Dorothy Bernstein
- Dot
- Dot product or Dot Product
- Dots and Boxes or Dots and boxes
- Double
- Double angle identity
- Double coset
- Double dagger
- Double dot
- Double exponential distribution
- Double factorial
- Double Integral or Double integral
- Double Mersenne number
- Double overhand knot
- Double point
- Double prime
- Double torus
- Double-angle formulas
- Double-periodic function
- Doublestruck
- Doublet
- Doubly periodic function
- Doubly Ruled Surface or Doubly ruled surface
- Doubly stochastic matrix
- Doughnut
- Dov Tamari
- Dowker notation
- Dozen
- Dragon curve
- Draughts
- Draw
- Drinfel'd module
- Drinfeld module
- Drum
- Ds
- Dt
- Du Bois-Reymond lemma
- Dual abelian variety
- Dual basis
- Dual bundle
- Dual category
- Dual code
- Dual cone
- Dual curve
- Dual graph
- Dual isogeny
- Dual number
- Dual pair
- Dual polyhedron
- Dual space
- Dual vector space
- Duality
- Duality Principle or Duality principle
- Duality theorem
- Duel
- Duffing differential equation
- Duffing equation
- Duhamel integral
- Dulmage-Mendelsohn Decomposition or Dulmage-Mendelsohn decomposition
- Dummy variable
- Dunkl operator
- Duodecillion
- Duodecimal
- Dupin cyclide
- Dupin indicatrix
- Duplicating the cube
- Duplication formula
- Duplication of the cube
- Dusa McDuff or Dusa mcduff
- Dust
- Dvoretzky's theorem
- Dyad
- Dyad product
- Dyadic
- Dyck language
- Dynamic game
- Dynamic programming
- Dynamical system
- Dynamics
- Dynkin diagram
- Dynkin index
- Dynkin system
