The difference between Dual and Number

Dual as an adjective:

Exhibiting duality; characterized by having two (usually equivalent) components.

Dual as an adjective:

Acting as a counterpart.

Dual as an adjective:

Double.

Dual as an adjective (grammar):

Pertaining to grammatical number (as in singular and plural), referring to two of something, such as a pair of shoes, in the context of the singular, plural and in some languages, trial grammatical number. Modern Arabic displays a dual number, as did Homeric Greek.

Dual as an adjective (linear algebra):

Being the space of all linear functionals of (some other space).

Dual as an adjective (category theory):

Being the dual of (some other category); containing the same objects but with source and target reversed for all morphisms.

Dual as a noun:

Of an item that is one of a pair, the other item in the pair.

Dual as a noun (geometry):

Of a regular polyhedron with V vertices and F faces, the regular polyhedron having F vertices and V faces.

Dual as a noun (grammar):

dual number The grammatical number of a noun marking two of something (as in singular, dual, plural), sometimes referring to two of anything (a couple of, exactly two of), or a chirality-marked pair (as in left and right, as with gloves or shoes) or in some languages as a discourse marker, "between you and me". A few languages display trial number.

Dual as a noun (mathematics):

Of a vector in an inner product space, the linear functional corresponding to taking the inner product with that vector. The set of all duals is a vector space called the dual space.

Dual as a verb (transitive):

To convert from single to dual; specifically, to convert a single-carriageway road to a dual carriageway.

Number as a noun (countable):

An abstract entity used to describe quantity.

Number as a noun (countable):

A numeral: a symbol for a non-negative integer.

Number as a noun (countable, mathematics):

A member of one of several classes: natural numbers, integers, rational numbers, real numbers, complex numbers, quaternions.

Number as a noun (Followed by a [[numeral]]; used [[attributive]]ly):

Indicating the position of something in a list or sequence. Abbreviations: No or No., no or no. (in each case, sometimes written with a superscript "o", like Nº or №). The symbol "#" is also used in this manner.

Number as a noun:

Quantity.

Number as a noun:

A sequence of digits and letters used to register people, automobiles, and various other items.

Number as a noun (countable, informal):

A telephone number.

Number as a noun (grammar):

Of a word or phrase, the state of being singular, dual or plural, shown by inflection.

Number as a noun (now, rare, in the plural):

Poetic metres; verses, rhymes.

Number as a noun (countable):

A performance; especially, a single song or song and dance routine within a larger show.

Number as a noun (countable, informal):

A person.

Number as a noun (countable, informal):

An item of clothing, particularly a stylish one.

Number as a noun (slang, chiefly, US):

A marijuana cigarette, or joint; also, a quantity of marijuana bought form a dealer.

Number as a noun (dated):

An issue of a periodical publication.

Number as a verb (transitive):

To label (items) with numbers; to assign numbers to (items).

Number as a verb (intransitive):

To total or count; to amount to.

Number as an adjective: