icosahedron 

noun ( icosahedr, a , pl2=icosahedrons)

(geometry) a polyhedron with twenty faces; the regular icosahedron has regular triangles as faces and is one of the Platonic solids.


ideal 

noun
 a perfect standard of beauty, intellect, etc., or a standard of excellence.

(algebra) A subring closed under multiplication by its containing ring.

(mathematics) In order theory, a special subset of a partially ordered set.
 an unattainable state/process in a given time/space but endlessly approachable.
adjective
 being optimal or relating to the best option for something.
 being perfect, having no flaws or defects.
 being something that exists only in the mind; CONCEPTUAL, ideational, IDEATIONAL,

Life and death appeared to me ideal bounds
 :" Wikipedia:Mary W. Shelley, Mary W. Shelley

idempotent 

adjective

(computing) Describing an action which, when performed multiple times, has no further effect on its subject after the first time it is performed.

identity element 

noun
(algebra) A member of a structure which, when applied to any other element via a binary operation induces an identity mapping; more specifically, given an operation

a left identity if I

x = x for any x in the structure

a right identity, x

I = x for any x in the structure

simply an identity element if both are true

identity matrix 

noun (pluralidentity matrices)

(linearalg) A diagonal matrix all of the diagonal elements of which are equal to 1.

IFF 

initialism
 Interchange File Format, a file format standard developed for Amiga computers.
 identification friend or foe

image 

noun
 An optical or other representation of a real object; a graphic; a picture.
 A mental picture of something not real or not present.

(computing) A copy of all or part of a disk drive retained for backup or replication purposes.
 A characteristic of a person, group or company etc., style, manner of dress, how one is, or wishes to be, perceived by others.

(mathematics) Something mapped to by a function.
5 is the of 3 under f.

(mathematics) The subset of a codomain comprising those elements that are images of something.
The of this step function is the set of integers.
verb (imag, ing)

(context, computing) To convert an idea to an image.

(context, computing) To create a complete backup copy of a filesystem.

imaginary 

adjective
 that exists only in the imagination

(mathematics) of, or being the imaginary part of a complex number

imaginary axis 

noun
(mathematics) The vertical line in the complex plane, every point on which corresponds to a complex number having zero real component

imaginary number 

noun (pluralimaginary numbers)

(complex) A number of the form ai, where a is a real number and i^{2} = −1; a complex number whose real part is zero.

imaginary part 

noun (pluralimaginary parts)

(complex) Of a complex number a + bi, the value b.

implicit 

adjective
 implied, Implied indirectly, without being directly expressed

1983, w:Ronald Reagan, Ronald Reagan, s:Proclamation 5018, Proclamation 5018

:The Bible and its teachings helped form the basis for the Founding Fathers' abiding belief in the inalienable rights of the individual, rights which they found in the Bible's teachings of the inherent worth and dignity of each individual.
 contained, Contained in the essential nature of something but not openly shown
 Having no reservations or doubts; unquestioning or unconditional; usually said of faith or trust.

1765, Anonymous, s:Considerations on Behalf of the Colonists, Considerations on Behalf of the Colonists

:He is not only a zealous advocate for pusilanimous and passive obedience, but for the most faith in the dictatorial mandates of power.

(obsolete) entangled, twisted together.

improper fraction 

noun (pluralimproper fractions)

(arithmetic) A vulgar fraction of which the numerator has a greater magnitude than the denominator, such as 3/2.

incircle 

noun (wikipedia, Incircle and excircles of a triangle)
 The circle within a triangle that is tangent to all three sides. The incentre is the center of this circle.

increasing 

verb

(present participle of, increase)

indefinite integral 

noun
(mathematics) A function whose derivative is a given function; an antiderivative

independent 

noun
 A candidate or voter not affiliated with any political party, a free thinker, free of a party platform.
 A neutral or uncommitted person.
adjective
 not dependent; not contingent or depending on something else; free

independent variable 

noun (pluralindependent variables)

(algebra) In an equation, any variable whose value is not dependent on any other in the equation.
In the equation z = x^{2} + y, x and y are the independent variables.

(science) The variable that is changed in an experiment.

indeterminate 

adjective
 not accurately determined or determinable
 imprecise or vague

induction 

noun
 the act of inducting
 a formal ceremony in which a person is inducted into an office or into military service

(physics) the generation of an electric current by a varying magnetic field

(logic) the derivation of general principles from specific instances

(mathematics) a general proof of a theorem by first proving it for a specific integer (for example) and showing that, if it is true for one integer then it must be true for the next
 the act of inducing childbirth
 In theatre, induction is the use of rumors to twist and complicate the plot of a play or to narrate in a way that does not have to state truth nor fact within the play.

(biology) In developmental biology, the development of a feature from part of a formerly homogenous field of cells in response to a morphogen whose source determines the feature's position and extent.

(obsolete) an introduction

inequality 

noun (inequalit, ies)
 An unfair, not equal, state.
The in living standards lead to a civil war as the have nots rebelled.

(mathematics) A statement that of two quantities one is specifically less than (or greater than) another.
The x is less than y, together with that y<z, allows us to deduce the x<z.

(context, mathematics, more, _, generally) A statement that of two quantities one is specifically less than (or greater than, or not less than, or not greater than) another.

infimum 

noun (infima)

(mathematics) (of a subset) the greatest element of the containing set that is smaller or equal to all elements of the subset. The infimum may or may not be a member of the subset.

infinite 

adjective
 boundless, Boundless, endless, without end or limits, uncountable, innumerable.

(mathematics) A number which is larger than any given number.

(figuratively) Very large.

infinitesimal 

noun
(mathematics) A nonzero quantity whose magnitude is smaller than any positive number (by definition it is not a real number).
adjective
 Too small to measure

(mathematics) Of or pertaining to values that approach zero as a limit

infinitesimal calculus 

noun (uncountable)

(calculus) differential calculus, Differential calculus and integral calculus considered together as a single subject.

inflection 

noun

(grammar) a change in the form of a word that reflects a change in grammatical function.
 a change in pitch or tone of voice.

(context, math) a change in curvature from concave to convex or from convex to concave.
 a turning away from a straight course.

inflection point 

noun

(mathematics) a point of inflection

injection 

noun
 The act of injecting, or something that is injected.

(context, specifically, medicine) Something injected subcutaneously, intravenously, or intramuscularly by use of a syringe and a needle.

(math) A function of "onetomany" mapping relationship; more formally, f: X → Y is an injection if and only if, for every x in the function domain, domain X, there is at least one y in the function codomain, codomain Y with f(x) = y.

inradius 

noun

(mathematics) the radius of the largest circle that will fit inside any given geometric shape, especially inside a regular polygon

(mathematics) the radus of the largest sphere that will fit inside any given polyhedron

inscribe 

verb (inscrib, ing)

(transitive) To write or cut words onto something, especially a hard surface; to engrave.

(geometry) To draw a circle, sphere, etc. inside a polygon, polyhedron, etc. and tangent to all its sides.

integer 

noun

(arithmetic) An element of the infinite and numerable set ...,3,2,1,0,1,2,3,....
adjective

(arithmetic) Of a number, whole.

integrable 

adjective

(calculus) Able to be integrated

integral 

noun

(mathematics) A numerical measure computed by a limiting process in which the domain of a function is divided into small subintervals and the value of the function at a point in each subinterval is multiplied by the measurement of that subinterval, all these products then being summed.

(mathematics) the result of summation of the product of a function and an infinitesimal.
adjective
 constitute, Constituting a whole together with other parts or factors; not omittable or removable

(mathematics) Of or relating to an integer.

integral calculus 

noun (uncountable)

(calculus) The calculus that generalizes summation to find areas, masses, volumes, sums, and totals of quantities described by continuously varying functions.

integral equation 

noun
(mathematics) An equation involving a function <math>f(x)</math> and integrals of that function to be solved for <math>f(x)</math>

integral function 

noun
(mathematics) An entire function

integrand 

noun

(calculus) The function that is to be integrated

integrate 

verb (integrates, integrating, integrated)
 To form into one whole; to make entire; to complete; to renew; to restore; to perfect.
 To indicate the whole of; to give the sum or total of; as, an integrating anemometer, one that indicates or registers the entire action of the wind in a given time.

(mathematics) To subject to the operation of integration; to find the integral of.
 To desegregate, as a school or neighborhood.

integration 

noun
 The act or process of making whole or entire.

(calculus) The operation of finding the integral of a function.
 In evolution, the process by which the manifold is compacted into the relatively simple and permanent; supposed to alternate with differentiation as an agent in development.

intercept 

noun (rfclevel, Noun at L4+ not in L3 POS section)
 An interception of a radio broadcast or a telephone call.
 An interception of a missile.

(alggeom) The coordinate of the point at which a curve intersects an axis.
verb

(transitive) To stop, deflect or divert (something in progress or motion).

(context, transitive, sports) To gain possession of (the ball) in a ball game.

interior 

noun
 The inside of a building, container, cavern, or other enclosed structure.
 The inside regions of a country, distanced from from the borders or coasts.
 ''Sir Richard Burton explored far into the African .
adjective
 having to do with the inner part of something
 having to do with the inland parts of a country far from the coasts

interior angle 

noun

(geometry) The inner angle between two sides of a polygon.

interpolate 

verb (interpolat, ing)
 To estimate the value of a function between two points between which it is tabulated.

(Computing) During the course of processing some data, and in response to a directive in that data, to fetch data from a different source and process it inline along with the original data.

intersect 

verb
 to cross each other; to cut each other

Parallel lines don't intersect.

(mathematics) two sets if and only if they have at least one common element

INTO 

initialism
 The Irish national teacher's organisation

invariant 

adjective
 never changing

inverse function 

noun
(mathematics) The function having as independent variable the dependent variable of another

inversely 

adverb
 In an inverse order or manner; by inversion.

inversion 

noun

(music) The move of one pitch in an interval or chord up or down an octave

(music) The reversal of an interval

(music) The reversal of the pitch contour

(music) The reversal of a pitch class succesion such as a melody or counterpoint, contrapuntal line

(music) Subtraction of pitch classes in a set from twelve which maps intervals onto their complements with respect to 0 and preserves interval classes, symbolized IX where X is the transposition which is inverted (DeLone? et. al. (Eds.), 1975, chap. 6).

(genetics) a segment of DNA in the context of a chromosome that is reversed in orientation relative to a reference karyotype or genome
 (Weather). An increase of air temperature with increase in altitude (the ground being colder than the surrounding air). When an inversion exists, there are no convection currents and wind speeds are below 5 knots. The atmosphere is stable and normally is considered the most favorable state for ground release of chemical agents.

(grammar) deviation, Deviation from standard word order by putting the predicate before the subject. It takes place in questions with auxiliary verbs and in normal, affirmative clauses beginning with a negative particle, for the purpose of emphasis.

(with an auxiliary verb) Inversion takes place in the sentence 'Is she here?' — 'is', the predicate, is before 'she', the subject.

(for the purpose of emphasis) Inversion takes place in the sentence 'Never have I done that.' — 'have', the predicate, is before 'I', the subject, due to 'never' being the first word of the sentence.

involute 

noun

(mathematics) A curve that cuts all tangents of another curve at right angles; traced by a point on a string that unwinds from a curved object.
adjective
 difficult to understand, or complicated

(context, botany, of a leaf or petal) having the edges rolled inwards

(context, biology, of some shells) having a complex pattern of coils

involution 

noun
 entanglement; a spiralling inwards; intricacy

1968: "Gomez," said the mortician, "is an expert only on the involutions of his own rectum." " Anthony Burgess, Enderby Outside

(mathematics) An endofunction whose square is equal to the identity function; a function equal to its inverse.

irrational 

adjective ((compar) more irrational, (superl) most irrational)
 Not rational; unfounded or nonsensical.
an irrational decision

(mathematics) (no comparative or superlative) Of a real number, that cannot be written as the ratio of two integers.
The number π is irrational.

irrational number 

noun (pluralirrational numbers)

(mathematics) Any real number that cannot be expressed as a ratio of two integers.

isogon 

noun A line of equal or constant wind direction on a graph or chart, such as a weather map.

isometric 

noun
 A line connecting isometric points.
adjective
 Of, or exhibiting equality in dimensions
 Of, or being a geometric system of three equal axes lying at right angles to each other (especially in crystallography).

(physiology) Of or involving muscular contraction against resistance in which the length of the muscle remains the same

(physics) (of a thermodynamic process) taking place at constant volume because of being confined by rigid boundaries

isometry 

noun (isometries)

(mathematics) A function between metric spaces (or on a single metric space) having the property that the distance between two images is equal to the distance between their preimages.

isomorphic 

adjective

(biology) having a similar structure to something that is not related genetically

(mathematics) related by an isomorphism

isomorphism 

noun

(biology) the similarity in form of organisms of different ancestry

(mathematics) a onetoone correspondence between all the elements of two sets such that any operation returns the same result on either set; a function that maps one of these sets to the other

(chemistry) the similarity in the crystal structures of similar chemical compounds

(sociology) the similarity in the structure or processes of different organizations

(computer science) a onetoone correspondence between all the elements of two sets, e.g. the instances of two classes, or the records in two datasets

isosceles 

adjective
(geometry) having two sides of equal length, used especially of an isosceles triangle.
