- T distribution
- T-design
- T-distribution
- T-Integration or T-integration
- T-Polyomino or T-polyomino
- T-Puzzle
- T0 space
- T0-separation axiom
- T0-space
- T1 space
- T1-separation axiom
- T1-space
- T2 space
- T2-separation axiom
- T2-space
- T3 space
- T3-separation axiom
- T3-space
- T4 space
- T4-separation axiom
- T4-space
- Tableau
- Tabu search
- Tacnode
- Tactix or TacTix
- Tag system
- Tail
- Tail event
- Tait coloring
- Takens-Bogdanov bifurcation
- Tamagawa measure
- Tamagawa number
- Tame knot
- Tan
- Tangent
- Tangent bundle
- Tangent Bundle Section or Tangent bundle section
- Tangent cone
- Tangent developable
- Tangent line
- Tangent Number or Tangent number
- Tangent plane
- Tangent space or Tangent Space
- Tangent Vector or Tangent vector
- Tangential quadrilateral
- Tangle
- Tangled Hierarchy or Tangled hierarchy
- Tangram
- Tanh
- Tanh-sinh quadrature
- Taniyama Conjecture or Taniyama conjecture
- Taniyama-Shimura Conjecture or Taniyama-Shimura conjecture
- Taniyama-Shimura theorem or Taniyama-Shimura Theorem
- Tank
- Tannakian category
- Tantrix
- Tarski's axiom
- Tarski's fixed point theorem
- Tarski's Theorem or Tarski's theorem
- Tarski-Knaster theorem
- Tate Conjecture or Tate conjecture
- Tate conjectures
- Tate module
- Tatyana Afanasyeva
- Tau
- Tau function
- Tau number
- Tauberian theorem
- Tauberian theorems
- Tautochrone
- Tautochrone Problem or Tautochrone problem
- Tautology
- Tautology (logic)
- Taxicab metric
- Taxicab number
- Taylor expansion
- Taylor formula
- Taylor polynomial
- Taylor series or Taylor Series
- Taylor theorem
- Taylor's theorem or Taylor's Theorem
- Tchebotarev density theorem
- Tchebycheff
- Tchirnhaus transformations
- Tebibyte
- Technique
- Teeko
- Teichmüller space
- Telegraph equation
- Teleparallelism
- Telescoping sum
- Temperature
- Tempered distribution
- Ten
- Tensegrity
- Tensor
- Tensor algebra
- Tensor analysis
- Tensor bundle
- Tensor calculus
- Tensor contraction
- Tensor density
- Tensor field
- Tensor index
- Tensor order
- Tensor product
- Tensor product of Hilbert spaces
- Tensor rank
- Tensor transformations
- Tent map
- Terabyte
- Terence Tao or Terence tao
- Term
- Term Rewriting System or Term rewriting system
- Terminal
- Terminal object
- Terminal symbol
- Termwise differentiation
- Ternary
- Ternary field
- Tessellation
- Tesseract
- Test statistic
- Testing
- Tests
- Tetrabolo
- Tetracontagon
- Tetractys
- Tetracuspid
- Tetrad
- Tetradecagon
- Tetradecahedron
- Tetraflexagon
- Tetragon
- Tetragonal trapezohedron
- Tetragram
- Tetrahedral group
- Tetrahedral number
- Tetrahedroid
- Tetrahedron
- Tetrahemihexahedron
- Tetrahexahedron
- Tetrakaidecagon
- Tetrakis Hexahedron or Tetrakis hexahedron
- Tetraktys
- Tetramagic Cube or Tetramagic cube
- Tetramagic Square or Tetramagic square
- Tetranacci Constant or Tetranacci constant
- Tetranacci Number or Tetranacci number
- Tetrastigm
- Tetration
- Tetraview
- Tetriamond
- Tetrix
- Tetromino
- Texas Instruments
- Text figures
- Tg
- Th
- Thabit ibn Qurra or Thabit ibn qurra
- Thabit number
- Thales' theorem or Thales' Theorem
- Themistius
- Theodolite
- Theodorus's constant
- Theophrastus
- Theorem
- Theorem of Pappus
- Theorem prover
- Theorema Egregium or Theorema egregium
- Theory
- Theory of algorithms
- Theory of automata
- Theory of Computation or Theory of computation
- Theory of errors
- Theory of games or Theory of Games
- Theory of gravitation
- Theory of invariants
- Theory of types
- Thermodynamic potential
- Thermodynamical limit
- Theta function
- Theta functions or Theta Functions
- Theta Operator
- Theta series
- Theta Subgroup or Theta subgroup
- Theta-function
- Theta-series
- Theta0 Graph or Theta0 graph
- Thickness
- Thiele's Interpolation Formula or Thiele's interpolation formula
- Thin plate spline
- Thin set
- Third group isomorphism theorem
- Third isomorphism theorem
- Third ring isomorphism theorem
- Thirteen
- Thom class
- Thom isomorphism
- Thom space
- Thom spectrum
- Thompson group
- Thompson Lamp Paradox or Thompson lamp paradox
- Thompson subgroup
- Thomson Cubic or Thomson cubic
- Thomson Problem or Thomson problem
- Thousand
- Thread
- Three
- Three-body problem
- Three circles theorem
- Three-Colorable Graph or Three-colorable graph
- Three-In-A-Row
- Three-valued logic
- Thue equation
- Thue sequence
- Thue's lemma
- Thue's theorem
- Thue-Morse constant
- Thue-Morse sequence
- Thue-Siegel-Roth theorem
- Thue-Siegel-Schneider-Roth Theorem or Thue-Siegel-Schneider-Roth theorem
- Thurston Elliptization Conjecture or Thurston elliptization conjecture
- Thurston's geometrization conjecture or Thurston's Geometrization Conjecture
- Thwaites conjecture
- Thâbit ibn Kurrah Number or Thâbit ibn Kurrah number
- Thâbit ibn Kurrah Rule or Thâbit ibn Kurrah rule
- Thébault's Theorem or Thébault's theorem
- Tic-Tac-Toe or Tic-tac-toe
- Ticktacktoe
- Tie
- Tietze extension theorem
- Tietze's extension theorem
- Tight
- Tight Closure or Tight closure
- Tight measure
- Tilde
- Tiling
- Time complexity
- Time invariant
- Time Series or Time series
- Time Series Analysis or Time series analysis
- Timelike
- Times
- Tit-for-Tat or Tit-for-tat
- Titanic Prime or Titanic prime
- Titchmarsh convolution theorem
- Tits group
- Tits system
- Tobias Dantzig
- Toda lattices
- Todd class
- Todd genus
- Todd polynomial
- Toeplitz matrix
- Tolerance
- Tolerance intervals
- Tomahawk
- Tomahawk (geometric shape)
- Tomita-Takesaki theory
- Tomography
- Tonelli theorem
- Tonelli's theorem or Tonelli's Theorem
- Top-dimensional form
- Topological Algebra or Topological algebra
- Topological basis
- Topological closure
- Topological conjugation
- Topological dimension
- Topological disc
- Topological divisor of zero
- Topological entropy
- Topological equivalence
- Topological field
- Topological graph
- Topological group or Topological Group
- Topological invariant
- Topological manifold
- Topological module
- Topological product
- Topological property
- Topological ring
- Topological sort
- Topological space
- Topological structures
- Topological sum
- Topological tensor product
- Topological transitivity
- Topological vector space
- Topologically conjugate
- Topologically transitive
- Topologist's sine curve
- Topology
- Topology of compact convergence
- Topology of pointwise convergence
- Topology of uniform convergence
- Topos
- Tor
- Tor functor
- Torelli theorems
- Toric section
- Toric variety
- Toroid
- Toroidal coordinates
- Torricelli's trumpet
- Torse
- Torsion
- Torsion (space curve)
- Torsion tensor
- Contorsion
- Torsor
- Torus
- Torus knot
- Total
- Total degree
- Total derivative
- Total differential
- Total function
- Total graph
- Total order
- Total positivity
- Total probability theorem
- Total recursive function
- Total ring of fractions
- Total space
- Total variation
- Total variation measure
- Total variation of a function
- Totally bounded
- Totally bounded space
- Totally disconnected space
- Totally multiplicative function
- Totally ordered group
- Totally ordered set
- Totally positive matrix or Totally Positive Matrix
- Totally symmetric polynomial
- Totally-bounded set
- Totally-bounded space
- Totally-disconnected space
- Totient
- Totient function
- Tour
- Tournament
- Tournament (graph theory)
- Tower of Hanoi or Tower of hanoi
- Tower of Power
- Towers of Hanoi or Towers of hanoi
- Toy theorem
- TQFT
- Trace
- Trace form
- Trace of a matrix
- Trace of a square matrix
- Trace-class operator
- Traceable graph
- Tractrisoid
- Tractrix
- Tractroid
- Trail
- Train track
- Trajectory
- Transcendence degree or Transcendence Degree
- Transcendental
- Transcendental curve
- Transcendental element
- Transcendental equation
- Transcendental extension
- Transcendental function
- Transcendental number or Transcendental Number
- Transcritical bifurcation
- Transfer function or Transfer Function
- Transfer principle
- Transfinite cardinal
- Transfinite induction or Transfinite Induction
- Transfinite number
- Transfinite ordinal
- Transfinite recursion
- Transfinite sequence
- Transform
- Transformation
- Transformation (mathematics)
- Transformation group
- Transformation semi-group
- Transformational grammar or Transformational Grammar
- Transgression
- Transit
- Transition function
- Transition probabilities
- Transitive
- Transitive closure
- Transitive group
- Transitive group action
- Transitive reduction
- Transitive relation
- Transitive set
- Transitivity
- Translate
- Translation
- Translation-invariant metric
- Transport equation
- Transport problem
- Transpose
- Transposed matrix
- Transposition
- Transposition (mathematics)
- Transvection
- Transversal intersection
- Transversal Line or Transversal line
- Transversality
- Transversality condition
- Transylvania lottery
- Trapdoor one-way function
- Trapdoor one-way hash function
- Trapezium
- Trapezium rule
- Trapezohedron
- Trapezoid
- Trapezoidal icositetrahedron
- Trapezoidal Rule or Trapezoidal rule
- Traveling Salesman Problem or Traveling salesman problem
- Travelling salesman problem
- Tredecillion
- Tree
- Tree (data structure)
- Tree (graph theory)
- Tree (set theoretic)
- Tree leaf
- Tree root
- Tree traversal
- Tree traversals
- Trefftz method
- Trefoil Curve or Trefoil curve
- Trefoil knot
- Tri-bar
- Triabolo
- Triacontagon
- Triacontahedron
- Triad
- Triads
- Triakis icosahedron
- Triakis octahedron
- Triakis tetrahedron
- Trial
- Trial division
- Trial divisor
- Triamond
- Triangle
- Triangle center or Triangle Center
- Triangle centre
- Triangle Centroid or Triangle centroid
- Triangle function
- Triangle geometry
- Triangle groups
- Triangle Inequalities or Triangle inequalities
- Triangle inequality
- Triangle line
- Triangle Median or Triangle median
- Triangle postulate
- Triangle tiling
- Triangle wave
- Triangle-free graph
- Triangular antiprism
- Triangular cupola
- Triangular Dipyramid or Triangular dipyramid
- Triangular distribution
- Triangular element
- Triangular graph
- Triangular group
- Triangular hebesphenorotunda
- Triangular Inequalities or Triangular inequalities
- Triangular matrix
- Triangular norm
- Triangular number
- Triangular numbers
- Triangular orthobicupola
- Triangular Prism or Triangular prism
- Triangular pyramid
- Triangular square number
- Triangular-wave function
- Triangulation
- Triaugmented dodecahedron
- Triaugmented hexagonal prism
- Triaugmented Triangular Prism or Triaugmented triangular prism
- Triaugmented truncated dodecahedron
- Tribar
- Tribonacci constant
- Tribonacci number
- Trichotomy
- Trichotomy law
- Tricomi equation
- Tricuspoid
- Tricylinder
- Tridecagon
- Trident
- Tridiagonal matrix or Tridiagonal Matrix
- Tridiminished icosahedron
- Tridiminished rhombicosidodecahedron
- Tridyakis icosahedron
- Trie
- Trifolium
- Trigamma function
- Trigon
- Trigonometric addition formulas
- Trigonometric Functions or Trigonometric functions
- Trigonometric interpolation
- Trigonometric polynomial
- Trigonometric series
- Trigonometric substitution
- Trigonometric sum
- Trigonometry
- Trigyrate rhombicosidodecahedron
- Trilinear coordinates
- Trillion
- Trilogarithm
- Trimagic cube
- Trimagic square
- Trimean
- Trimmed mean
- Trimorphic number
- Trinomial
- Trinomial Identity or Trinomial identity
- Trio
- Triomino
- Trip-let
- Triple
- Triple integral
- Triple Jacobi product
- Triple Point or Triple point
- Triple product
- Triple product identity
- Triple scalar product
- Triple vector product
- Triplet
- Tripolar
- Triquetra
- Trisection
- Trisection of an angle
- Trisection of angle
- Trisectrix
- Trisectrix of Maclaurin
- Triskaidecagon
- Triskaidekaphobia
- Trisoctahedron
- Trivalent graph
- Trivector
- Trivial
- Trivial bundle
- Trivial group
- Trivial knot
- Trivial Link or Trivial link
- Trivial module
- Trivial representation
- Trivial ring
- Trivial topology
- Trivium
- Trochoid
- Tromino
- Tropical year
- Trough
- True
- Truncatable prime
- Truncate
- Truncated cone
- Truncated cube
- Truncated cuboctahedron
- Truncated distribution
- Truncated dodecadodecahedron
- Truncated dodecahedron
- Truncated great dodecahedron
- Truncated great icosahedron
- Truncated hexahedron
- Truncated Icosahedron or Truncated icosahedron
- Truncated icosidodecahedron
- Truncated octahedron
- Truncated polyhedron
- Truncated power function
- Truncated Pyramid or Truncated pyramid
- Truncated Square Pyramid or Truncated square pyramid
- Truncated tetrahedron
- Truncation
- Truth function
- Truth table or Truth Table
- Truth value
- Tschebyshev
- Tschirnhausen cubic
- Tschirnhausen transformation
- Tsirelson space
- Tsuneo Tamagawa
- Tube
- Tube lemma
- Tubular neighborhood
- Tubular neighbourhood
- Tunnell's theorem
- Tuple
- Tupper's self-referential formula
- Turan's theorem
- Turbine
- Turing machine or Turing Machine
- Turmite
- Turtle
- Turtle Geometry or Turtle geometry
- Turán graph
- Turán's theorem or Turan's theorem
- Tusi couple
- Tutte polynomial
- Tutte theorem
- Tutte's theorem
- Tutte-Coxeter graph
- Twiddle
- Twig
- Twin Peaks or Twin peaks
- Twin prime conjecture or Twin Prime Conjecture
- Twin primes
- Twin primes constant
- Twins
- Twirl or TWIRL
- Twist
- Twisted Chevalley groups
- Twisted cubic
- Twisted K-theory
- Twisted Sphere or Twisted sphere
- Twistor
- Twistor space
- Two
- Two-body problem
- Two-colorable graph
- Two-form
- Two-graph
- Two-person zero-sum game
- Two-point tensor
- Two-sided ideal
- Two-valued logic
- Tychonoff
- Tychonoff compactness theorem
- Tychonoff fixed point theorem
- Tychonoff space
- Tychonoff theorem
- Tychonoff topology
- Tychonoff's theorem
- Type
- Type I Error or Type I error
- Type II Error or Type II error
- Type theory or Type Theory
