Delta (letter)

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Delta (letter)

Delta (uppercase ?, lowercase d; Thelta) is the fourth letter of the Greek alphabet

Greek alphabet

The Greek alphabet is a set of twenty-four letters that has been used to write the Greek language since the late 9th century BC or early 8th century BCE....
. In the system of Greek numerals

Greek numerals

Greek numerals are a numeral system using letters of the Greek alphabet. They are also known by the names Milesian numerals, Alexandrian numerals, or alphabetic numerals....
it has a value of 4. It was derived from the Phoenician letter

Phoenician alphabet

The Phoenician alphabet is a continuation of the Proto-Canaanite alphabet, by convention taken to originate around 1050 BC. It was used for the writing of Phoenician language, a Northern Semitic languages language, used by the civilization of Phoenicia....
Dalet, but in the Ancient Greek

Ancient Greek

Ancient Greek is the historical stage in the development of the Greek language spanning across the Archaic Greece , Classical Greece , and Hellenistic civilization periods of ancient Greece and the classical antiquity....
language, it represented a voiced dental plosive

Voiced dental plosive

The voiced dental plosive is a type of consonantal sound, used in some Speech communication languages. The symbol in the International Phonetic Alphabet that represents this sound is , and the equivalent X-SAMPA symbol is d_d....
.

A river delta

River delta

A delta is a landform that is created at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river....
is so named because its shape approximates the upper-case letter delta.

upper-case letter ? can be used to denote

, the average change of y per unit x, i.e.

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Delta (uppercase ?, lowercase d; Thelta) is the fourth letter of the Greek alphabet

Greek alphabet

The Greek alphabet is a set of twenty-four letters that has been used to write the Greek language since the late 9th century BC or early 8th century BCE....
. In the system of Greek numerals

Greek numerals

Phoenician alphabet

Ancient Greek

Voiced dental plosive

River delta

The upper-case letter ?

The upper-case letter ? can be used to denote

Change
Difference operator

In mathematics, a difference operator maps a function , , to another function, .The forward difference operatoroccurs frequently in the calculus of finite differences, where it plays a role formally similar to that of the derivative, but used in discrete circumstances....
; e.g. in

, the average change of y per unit x, i.e. the change of y over the change of x

More specifically, the difference operator
Difference operator

In mathematics, a difference operator maps a function , , to another function, .The forward difference operatoroccurs frequently in the calculus of finite differences, where it plays a role formally similar to that of the derivative, but used in discrete circumstances....
.
The Laplace operator
Laplace operator

In mathematics and physics, the Laplace operator or Laplacian, denoted by or and named after Pierre-Simon de Laplace, is a differential operator, specifically an important case of an elliptic operator, with many applications....
:
The discriminant
Discriminant

In algebra, the discriminant of a polynomial with real number or complex number coefficients is a certain expression in the coefficients of the polynomial which is equal to zero if and only if the polynomial has a multiple Root in the complex numbers....
of a polynomial
Polynomial

In mathematics, a polynomial is an expression constructed from variables and constants, using the operations of addition, subtraction, multiplication, and constant non-negative whole number exponents....
equation, especially the quadratic equation
Quadratic equation

In mathematics, a quadratic equation is a polynomial equation of the second degree of a polynomial. The general form iswhere a ? 0. The letters a, b, and c are called coefficients: the quadratic coefficient a is the coefficient of x2, the linear coefficient b is the coefficient of x, and c i...
:
A macroscopic change
Derivative

In calculus, a branch of mathematics, the derivative is a measure of how a function changes as its input changes. Loosely speaking, a derivative can be thought of as how much a quantity is changing at a given point....
in the value of a variable in mathematics or science
Uncertainty
Uncertainty

Uncertainty is a term used in subtly different ways in a number of fields, including philosophy, Uncertainty_principle , statistics, economics, finance, insurance, psychology, sociology, engineering, and information science....
in a physical variable as seen in for instance the uncertainty principle
Uncertainty principle

In quantum physics, the Werner Heisenberg uncertainty principle states that certain physical quantities, like the position and momentum, cannot both have precise values at the same time....
A interval of possible values for a given quantity for instance across a sample
Any of the delta particles
Baryon

Baryons are the family of composite particle subatomic particle made of three quarks, as opposed to the mesons which are the family of composite particles made of one quark and one antiquark....
in particle physics
The determinant of the matrix of coefficients of a set of linear equations (see Cramer's Rule
Cramer's rule

Cramer's rule is a theorem in linear algebra, which gives the solution of a system of linear equations or corresponding square matrices in terms of determinants....
)
That an associated locant
Locant

A locant can be used in organic chemistry to indicate the position of a functional group within a molecule . For example, there are at least two isomers of the linear form of pentanone, a ketone that contains a chain of exactly five carbon atoms....
number represents the location of a covalent bond
Covalent bond

A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms, or between atoms and other covalent bonds....
in an organic compound
Organic compound

An organic compound is any member of a large class of chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of compounds such as carbonates, simple oxides of carbon and cyanides, as well as the allotropes of carbon, are considered Inorganic compound....
, the position of which is variant between isomeric forms
In legal shorthand, it represents a defendant
Defendant

A defendant or defender is any party who is required to answer the complaint of a plaintiff or pursuer in a civil lawsuit before a court, or any party who has been formally indictment or accused of violating a crime statute....
In the financial markets, it is one of the Greeks
Greeks (finance)

In mathematical finance, the Greeks are the quantities representing the sensitivities of derivative such as option to a change in underlying parameters on which the value of an instrument or Portfolio of financial instruments is dependent....
that describes the rate of change of an option price for a given change in the underlying benchmark
In genetics
Genetics

Genetics , a discipline of biology, is the science of heredity and Genetic variation in living organisms. The fact that living things inherit traits from their parents has been used since prehistoric times to improve crop plants and animals through selective breeding....
, it can stand for a gene deletion, e.g. the CCR5-?32
CCR5

CCR5, short for chemokine receptor 5 is a protein which in humans is encoded by the CCR5 gene which is located on chromosome 3 on the short arm at position 21....
a deletion of the CCR5 at the 32nd bp segment
In chemistry, it denotes the change in a physical property such as heat, e.g. ?Temp would stand for the change in Temp
The cites it (together with omicron for "odont") as the symbol of dentistry.

The lower-case letter d

The lower-case letter d can be used to denote

An infinitesimal change in the value of a variable in infinitesimal calculus
Infinitesimal calculus

Infinitesimal calculus was independently invented by both Gottfried Leibniz and Isaac Newton in the 1660s, drawing on the work of such mathematicians as Isaac Barrow and Rene Descartes....
An auxiliary function in Calculus
Calculus

Calculus is a branch of mathematics that includes the study of limit , derivatives, integrals, and infinite series, and constitutes a major part of modern university education....
used to rigorously define the limit
Limit of a function

In mathematics, the limit of a function is a fundamental concept in calculus and mathematical analysis concerning the behavior of that Function near a particular independent variable....
or continuity
Continuous function

In mathematics, a continuous function is a function for which, intuitively, small changes in the input result in small changes in the output. Otherwise, a function is said to be discontinuous....
of a given function.
The Kronecker delta
Kronecker delta

In mathematics, the Kronecker delta or Kronecker's delta, named after Leopold Kronecker , is a Function of two variables, usually integers, which is 1 if they are equal, and 0 otherwise....
in mathematics
The Dirac delta function
Dirac delta function

The Dirac delta or Dirac's delta is a mathematics construct introduced by theoretical physicist Paul Dirac. Informally, it is a function representing an infinitely sharp peak bounding unit area: a function d that has the value 0 everywhere except at x = 0 where its value is infinity in such a way that its total integral is 1....
in mathematics
The transition function
Transition function

In mathematics, a transition function has several different meanings:* In topology, a transition function is a homeomorphism from one coordinate chart to another....
in automata
Finite state machine

A finite state machine or finite state automaton or simply a state machine, is a model of behavior composed of a finite number of state s, transitions between those states, and actions....
Deflection
Deflection

Deflection or deflexion may refer to:*Deflection *Deflection *Deflection *Electrostatic deflection*Deflection ...
in engineering mechanics
The Force of Interest
Compound interest

Compound interest is the concept of adding accumulated interest back to the principal, so that interest is earned on interest from that moment on....
in actuarial science
The chemical shift
Chemical shift

In nuclear magnetic resonance , the chemical shift describes the dependence of nuclear magnetic energy levels on the electronic environment in a molecule....
of Nuclear Magnetic Resonance
Nuclear magnetic resonance

Nuclear magnetic resonance is the name given to a physical resonance phenomenon involving the observation of specific quantum mechanics magnetism properties of an atomic atomic nucleus in the presence of an applied, external magnetic field....
in chemistry
The relative electronegativity
Electronegativity

Electronegativity, symbol χ, is a chemical property that describes the ability of an atom to attract electrons towards itself in a covalent bond....
of different atoms in a molecule, d⁻ being more electronegative than d⁺
Text requiring deletion in proofreading
Proofreading

Proof-reading traditionally means reading a proof copy of a writing in order to detect and correct any errors. Modern proofreading often requires reading Copy at earlier stages as well....
. The usage is said to date back to classical times
In some of the manuscripts written by Dr. John Dee
John Dee (mathematician)

John Dee was a noted England mathematics, astronomy, astrology, geography, Occultism, and consultant to Queen Elizabeth I of England. He also devoted much of his life to the study of alchemy, divination, and Hermeticism....
, the character of delta is used to represent Dee
The Computer Science chapter at the Royal Institute of Technology
Royal Institute of Technology

The Royal Institute of Technology is a university in Stockholm, Sweden. KTH was founded in 1827 as Sweden's first polytechnic and is with TKK in Helsinki, depending on definition, Scandinavia's largest institution of higher education in technology and one of the leading technical universities in Europe ....
Is a subunit of the F1 sector of the F-ATPase
F-ATPase

F-ATPase, also known as F-Type ATPase, is a transmembrane protein found in bacterial plasma membranes, mitochondrial inner membranes and in chloroplast thylakoid....
The declination
Declination

In astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle....
of an object in the equatorial coordinate system
Equatorial coordinate system

The equatorial coordinate system is probably the most widely used celestial coordinate system, whose equatorial coordinates are:* declination ...
of astronomy
Astronomy

Astronomy is the science of Astronomical object and Phenomenon that originate outside the Earth's atmosphere . It is concerned with the evolution, physics, chemistry, meteorology, and motion of celestial objects, as well as the physical cosmology....
The dividend yield on the Black-Scholes
Black-Scholes

The term Black?Scholes refers to three closely related concepts:* The #Black?Scholes model is a mathematical model of the market for an Stock, in which the equity's price is a stochastic process....
option pricing formula
Ratios of environmental isotopes
Environmental isotopes

The environmental isotopes are a subset of the isotopes, both Stable isotopes and Radioactive isotopes, which are the object of Isotope geochemistry....
, such as ¹⁸O/¹⁶O and D
Deuterium

Deuterium, also called heavy hydrogen, is a stable isotope of hydrogen with a natural abundance in the oceans of Earth of approximately one atom in 6500 of hydrogen ....
/¹H from waters are displayed using delta notation
Isotope geochemistry

Isotope geochemistry is an aspect of geology based upon study of the relative and absolute concentrations of the chemical element and their isotopes in the Earth....
- d¹⁸O and dD, respectively.

Delta (letter)

The upper-case letter ?

The lower-case letter d

See also