In this article, you will find a comprehensive list of math words that start with the letter “D.

**Data-**Information collected for analysis**Decimal-**A number with a point dividing the whole and fractional parts**Degree-**Unit of measurement for angles**Denominator-**The bottom number in a fraction**Diameter-**A straight line passing through the center of a circle**Difference-**The result of subtraction**Digit-**A single numeral (0-9)**Dimension-**A measurable extent of some kind, such as length, breadth, depth, or height**Direct Proportion-**A relationship where one quantity increases as another increases**Distributive Property-**a(b + c) = ab + ac, distribution over addition or subtraction**Divisor-**The number by which another number is divided**Dividend-**The number to be divided**Division-**The process of determining how many times one number is contained within another**Dodecahedron-**A three-dimensional shape with 12 flat faces**Domain-**The set of possible input values (x-values) for a function**Diagonal-**A line segment joining two non-adjacent vertices of a polygon**Differential-**Relating to the difference of quantities**Degree of Polynomial-**The highest power of the variable in a polynomial**Dependent Variable-**A variable whose value depends on another**Decomposition-**Breaking down a number into smaller parts**Deduction-**Deriving conclusions through logical reasoning**Degree of a Graph-**The number of edges incident to a vertex**Duality-**Concept where structures have a complementary counterpart**Disjoint Sets-**Sets that have no elements in common**Differential Equation-**An equation involving derivatives**Discrete Mathematics-**Branch of math dealing with countable, distinct elements**Disjoint-**Mutually exclusive or having no intersection**Deviation-**Difference from a standard or average**Depreciation-**The reduction in value of an asset over time**Directrix-**A fixed line used in describing a curve or surface**Dilation-**Transformation altering the size but not the shape**Discriminant-**Part of the quadratic formula, b² – 4ac**Dot Product-**Scalar product of two vectors**Determinant-**A value calculated from a square matrix**Derivative-**The rate of change of a function with respect to a variable**Distribution-**A function showing the range of possible values for a variable**Diophantine Equation-**Polynomial equations with integer solutions**Dual Space-**Set of linear functionals on a vector space**Directional Derivative-**Rate of change of a function in a given direction**Double Integral-**Integration over a two-dimensional area**Dynamic-**Relating to a process of change**Difference of Squares-**a² – b² = (a + b)(a – b)**Dichotomy-**Division into two mutually exclusive groups**Discrete Variable-**A variable that can take on a finite or countable number of values**Diagonal Matrix-**A matrix with non-zero elements only on the diagonal**Divisibility-**The ability of one number to be divided by another without a remainder**Duality Principle-**Interchange properties in mathematical proofs**Distribution Property-**Property of distributing operations over functions**Differential Calculus-**The study of how functions change when their inputs change**Discrete Probability-**The probability of outcomes in a discrete sample space**Direct Method-**Solving linear equations by directly manipulating them**Disjoint Union-**Combination of disjoint sets**Discrete Distribution-**Probability distribution for discrete random variables**Division Algorithm-**The method of dividing polynomials**Dimensional Analysis-**Analysis of units and their consistency**De Morgan’s Laws-**Laws relating union and intersection of sets**Discrete Fourier Transform-**Transform used in signal processing**Definite Integral-**Integral evaluated over a specific interval**Domain of Definition-**The set of values for which a function is defined**Deterministic Model-**A model where outcomes are precisely determined**Difference Operator-**Operator expressing finite differences**Disjunctive Normal Form-**Standard form in boolean algebra**Decision Tree-**A branching method to reach decisions based on conditions**Differential Geometry-**Study of curves and surfaces through calculus**Dimensionality Reduction-**Reducing the number of variables under consideration**Distance Formula-**Formula to calculate distance between two points**Discrete Event Simulation-**Simulation of processes in discrete steps**Discrete Optimization-**Optimization problem over discrete spaces**Digest Function-**Function that transforms data into fixed-size hash**Degrees of Freedom-**The number of values in a calculation that are free to vary**Discrepancy-**Difference between expected and actual values**Dynamic Programming-**Method for solving complex problems by breaking them down**Doubling Time-**Time required for a quantity to double in size**Difference Quotient-**The ratio of change in function value to change in variable**Dual Graph-**A graph associating polygon vertices and edges to another**Disjoint Partition-**A partition where subsets have no elements in common**Divisible-**Capable of being divided by another number without remainder**Discrete Logarithm-**Logarithm in terms of integers over modular arithmetic**Discrete Set-**A set of distinct and separate values**Distributed Processing-**Processing spread over multiple systems**Discreteness-**Quality of being separate or distinct**Decay Rate-**The rate at which a substance decreases over time**Discovery Learning-**Learning approach through discovery and exploration**Discrete Cosine Transform-**Similar to Fourier transform, used in signal processing**Data Mining-**Extracting useful information from large data sets**Design Matrix-**A matrix of data for statistical models**Discontinuity-**A point where a mathematical function is not continuous**Discrete Sampling-**Sampling at distinct intervals**Decision Boundary-**Separation in space used in classification problems**Deconvolution-**Reversing the effect of convolution on data**Deterministic-**Predictable with no randomness involved**Derivative Test-**Test using derivatives to find local extrema**Double Counting-**Counting an event more than once**Divide-**and-Conquer Algorithm – Algorithm breaking problems into smaller subproblems**Damped Oscillation-**Oscillation reduced over time due to damping**Data Frame-**Structure for storing data in grids**Deadlock-**A situation where processes cannot proceed due to dependency**Degree Sequence-**Sequence of vertex degrees in a graph**Dichotomous Variable-**A variable with only two possible values**Dynamic Range-**The ratio between the largest and smallest possible values