different between dual vs twofold

English

Alternative forms

• du. (abbreviation, grammar)

Etymology

Borrowed from Latin dualis (“two”), from duo (“two”) + adjective suffix -alis

Pronunciation

• (UK) enPR: dyo?o'?l, djo?o'?l; IPA^(key): /?dju?.?l/, /?d?u?.?l/
• (US) enPR: d(y)o?o'?l; IPA^(key): /?d(j)u?.?l/
• Rhymes: -??l
• Homophone: duel

Adjective

dual (not comparable)

1. Exhibiting duality; characterized by having two (usually equivalent) components.
2. Acting as a counterpart.
3. Double.

4. (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.

5. (linear algebra) Being the space of all linear functionals of (some other space).
   • 2012, Doug Fisher, Hans-J. Lenz, Learning from Data: Artificial Intelligence and Statistics V, Springer Science & Business Media ?ISBN, page 81

     Accordingly, a hyperplane in the sample space is dual to a subspace in the variable space.

6. (category theory) Being the dual of some other category; containing the same objects but with source and target reversed for all morphisms.
   • 1992, Colin McLarty, Elementary Categories, Elementary Toposes, Clarendon Press ?ISBN, page 77

     Every category is dual to its own dual, so if a statement holds in all categories so does its dual.

Synonyms

• (having two components): double, twin; see also Thesaurus:dual
• (double): double, duplicate; see also Thesaurus:twofold
• (category theory): opposite

Derived terms

Translations

Noun

dual (plural duals)

1. Of an item that is one of a pair, the other item in the pair.
2. (geometry) Of a regular polyhedron with V vertices and F faces, the regular polyhedron having F vertices and V faces.

3. (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.
4. (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.

Translations

See also

• (grammatical numbers) grammatical number; singular, dual, trial, quadral, paucal, plural ^{(Category: en:Grammar)}
• unal
• duel

Verb

dual (third-person singular simple present duals, present participle (UK) dualling or (US) dualing, simple past and past participle (UK) dualled or (US) dualed)

1. (transitive) To convert from single to dual; specifically, to convert a single-carriageway road to a dual carriageway.
   • 1994, Great Britain. Parliament. House of Commons, Parliamentary Debates

     I have to declare an interest and I do so with some ambivalence because if the road is dualled it is likely to take half of my front garden.

   • 1998, Great Britain. Parliament. House of Commons, Parliamentary Debates

     Way back in 1971, the Government of the day first published plans for a high-capacity road network, which included the dualling of the A47 from King's Lynn to Great Yarmouth.

   • 2006, David Lowe, Intermodal Freight Transport, p. 163

     The power generation and propulsion systems are dualled to accommodate component failure and maintain propulsion at reduced speed should any part of one system be lost.

Anagrams

• Auld, Daul, Dula, auld, laud, udal

German

Pronunciation

• IPA^(key): [du?a?l]
• Hyphenation: du?al
• Rhymes: -a?l

Adjective

dual (not comparable)

1. dual

Declension

Further reading

• “dual” in Duden online

Irish

Pronunciation

• IPA^(key): /d??u?l?/

Etymology 1

From Old Irish dúal (“tress, lock of hair”), from Proto-Celtic *doklos, from Proto-Indo-European *do?los (compare Icelandic tagl (“horse’s tail”), Old English tæ?l, English tail).

Noun

dual m (genitive singular duail, nominative plural duail)

1. lock, tress

   Synonyms: dlaoi, dual gruaige

2. wisp, tuft

   Synonym: dlaoi

3. ply, strand
4. twist, twine
5. spiral, whirl

Declension

Derived terms

• dualach¹

Verb

dual (present analytic dualann, future analytic dualfaidh, verbal noun dualadh, past participle dualta)

1. (transitive) twine
2. (transitive) braid, coil
3. (transitive) interlace, fold

Conjugation

Etymology 2

(This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium.)

Noun

dual m (genitive singular duail, nominative plural duail)

1. dowel
2. knot (in timber)

   Synonyms: alt, cranra

Declension

Derived terms

• dualach²
• dualbhata

Etymology 3

From Old Irish dúal (“that which belongs or is proper to an individual by nature or descent”), from Proto-Indo-European *d?ewg?-.

Adjective

dual (genitive singular masculine duail, genitive singular feminine duaile, plural duala, comparative duaile)

1. native, natural

2. proper, fitting
3. in the natural order of things
4. fated
5. possible

Declension

Mutation

Further reading

• "dual" in Foclóir Gaeilge–Béarla, An Gúm, 1977, by Niall Ó Dónaill.
• Gregory Toner, Maire Ní Mhaonaigh, Sharon Arbuthnot, Dagmar Wodtko, Maire-Luise Theuerkauf, editors (2019) , “1 dúal”, in eDIL: Electronic Dictionary of the Irish Language
• Gregory Toner, Maire Ní Mhaonaigh, Sharon Arbuthnot, Dagmar Wodtko, Maire-Luise Theuerkauf, editors (2019) , “2 dúal”, in eDIL: Electronic Dictionary of the Irish Language
• Entries containing “dual” in English-Irish Dictionary, An Gúm, 1959, by Tomás de Bhaldraithe.
• Entries containing “dual” in New English-Irish Dictionary by Foras na Gaeilge.

Portuguese

Adjective

dual m or f (plural duais, comparable)

1. dual (having two elements)

Romanian

Etymology

From French duel, from Latin dualis.

Noun

dual n (plural duale)

1. (grammar) dual

Declension

Scottish Gaelic

Etymology 1

From Old Irish dúal (“that which belongs or is proper to an individual by nature or descent”), from Proto-Indo-European *d?ewg?-.

Pronunciation

• IPA^(key): /t?u???/

Adjective

dual (comparative duaile)

1. hereditary
2. usual, natural

Noun

dual m (genitive singular duail, plural dualan)

1. birthright

   Synonym: còir-bhreith

2. due
3. something which is natural and/or usual

Derived terms

• bu dual do dh'isean an ròin a dhol chun na mara

Etymology 2

From Old Irish dúal (“tress, lock of hair”), from Proto-Celtic *doklos, from Proto-Indo-European *do?los.

Noun

dual m (genitive singular duail, plural dualan)

1. curl, lock of hair
2. plait, strand, braid, or fold
3. ringlet

Verb

dual (past dhual, future dualidh, verbal noun dualadh, past participle dualte)

1. plait, twist
2. loop, curl
3. fold
4. link

Mutation

References

• MacBain, Alexander; Mackay, Eneas (1911) , “dual”, in An Etymological Dictionary of the Gaelic Language, Stirling, ?ISBN, page 145

Further reading

• Gregory Toner, Maire Ní Mhaonaigh, Sharon Arbuthnot, Dagmar Wodtko, Maire-Luise Theuerkauf, editors (2019) , “1 dúal”, in eDIL: Electronic Dictionary of the Irish Language
• Gregory Toner, Maire Ní Mhaonaigh, Sharon Arbuthnot, Dagmar Wodtko, Maire-Luise Theuerkauf, editors (2019) , “2 dúal”, in eDIL: Electronic Dictionary of the Irish Language

Spanish

Pronunciation

• Rhymes: -al

Adjective

dual (plural duales)

1. dual
2. (grammar) dual

English

Alternative forms

• two-fold

Etymology

From Middle English twofold, from Old English tw?ofeald. Equivalent to two +? -fold; cognate to Icelandic tvöfalt and Dutch tweevoudig.

Adjective

twofold (not comparable)

1. Double; duplicate; multiplied by two.

   The wheat produced a twofold harvest.

2. Having two parts, especially two different parts.

   a twofold nature; a twofold sense; a twofold argument

   • 1874, Ernest Myers (transl.), The Extant Odes of Pindar, translated into English, Pythian Ode III, page 65.

     Had I but landed there and brought unto him a twofold joy, first golden health and next this my song of triumph to be a splendour in his Pythian crown […]

   • 2014, Robert K. Bolger, Scott Korb, "Gesturing Toward Reality: David Foster Wallace and Philosophy

     "Wallace's suggestion for overcoming the epistemological and solipsistic effects of innate selfishness is twofold."

Synonyms

• (double): double, duplicate; see also Thesaurus:twofold
• (having two parts): twin; see also Thesaurus:dual

Derived terms

• twofoldness

Translations

Adverb

twofold (not comparable)

1. In a double degree; doubly.

Synonyms

• double; see also Thesaurus:twice

Translations

References

• twofold in The Century Dictionary, New York, N.Y.: The Century Co., 1911.
• twofold in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913.