dvi
number two.
A. Meanings
I. Two as unit

with objective foundation:
 denoting a combination (pair, couple) or a repetition (twice). In this conn. frequent both objective & impersonal in mentioning natural pairs as well as psychologically contrasted notions. E.g. dvipad (biped), nāgassa dve dantā (elephants’ tusks), cakkhūni (eyes); dvija (bird), duvija (tooth), dijivha (snake) See also dutiya & dvaya
■ dve: kāmā, khiḍḍā, gatiyo (Snp.1001), dānāni (Iti.98), piyā, phalāni (Snp.896; Iti.39), mittā, sinehā etc. See Nd ii.under dve, cp. AN.i.47 AN.i.100; DN.iii.212–DN.iii.214  denoting a separation (in two, twofold etc.): see dvidhā & compounds
 denoting a combination (pair, couple) or a repetition (twice). In this conn. frequent both objective & impersonal in mentioning natural pairs as well as psychologically contrasted notions. E.g. dvipad (biped), nāgassa dve dantā (elephants’ tusks), cakkhūni (eyes); dvija (bird), duvija (tooth), dijivha (snake) See also dutiya & dvaya

with symbolic, sentimental meaning:
 only two (i.e. next to one or “next to nothing”), cp. the two mites of the widow (Mark xii. 42), two sons of Rachel (Gen. 30) dumāsika not more th an.2 months (Vin.ii.107); dvemāsiko gabbho (Pv.i.6#7); dvevācika; duvangula (see below)
 a few more than one, some, a couple (often intermediate between 1 & 3, denoting more than once, or a comparatively long, rather long, but not like 3 a; very long time): māsadvayaṃ a couple of months dvisahassa dīpā 2000 islands (= a large number) diyaḍḍhasata 150 = very long etc.; dvīhatīha (2 or 3 a couple of days) q.v.; dvirattatiratta (id. of nights) dvīsu tīsu manussesu to some people (Pva.47); dvatikkhattuṃ soveral times; cp. dvikkhattuṃ (more than once), dutiyaṃ (for the second time).
II. Two as unit
in connection with its own & other.
decimals means a complex plus a pair, which amounts to the same as a large & a small unit, or so to speak “a year & a day.” E.g. 12 (sometimes, but rarely 10 + 2, see sep.);  32: rests usually on 4 × 8, but as No. of the Mahāpurisalakkhaṇāni it denotes 30 + 2 the great circle plus the decisive (invisible) pair;  62 views of heresy: see diṭṭhi; also as a year of eternity 60 kappas + 2;  92: as measure of eternity = 90 + 2 kappas = a year & a day.
III. Number twelve
 Based on natural phenomena it denotes the solar year (dvādasamāsako saṃvaccharo Vva.247).
 Connected with the solar cult it is used with human arrangements to raise them to the level of heavenly ones and to impart to them a superior significance. Thus:
 as denoting a set (cp. 12 months = companions of the Sun) it is the No. of a respectful holy, venerable group (cp. 12 sons of Jacob Gen. 35, 22 cakes as shewbread Lev. 25, 5; stones erected Josh. 4 8; apostles Math. 10, 2; patriarchs Acts 7, 8; companions of Odysseus Hom. Od. 9, 195; Knights of Arthur etc.): of theras, accomp^{d} by 12 bhikkhus Pva.67, Pva.141. 179 etc.; dvādasa koṭisatāni Snp.677; five groups of 12 musicians Vva.96 (cp. 5 × 12 cromlechs in the outer circle of Stonehenge)
 as measure of distance in space & time it implies vast extent great importance, a climax, divine symmetry etc 12 yojanas wide extends the radiance Vva.16 Vva.12 y. as respectful distance Pva.137 (cp. 2000 cubits in same sense at Josh. 3, 4); Pva.12 y. in extent (height breadth & length) are the heavenly palaces of the Vimānapetas or Yakkhas Vv.55#1; Ja.vi.116; Vva.6 Vva.217, Vva.244, Vva.291, Vva.298 etc. In the same connection we freq. find the No. 16: solasayojanikaṃ kanakavimānaṃ Vv.67#1; Vva.188, Vva.289 etc
■ Of years: Ja.iii.80; Vva.157 (dvādasavassikā; in this sense also 16 instead of 12 soḷasavassuddesika Vva.259 etc. See soḷasa).
B. Bases & Forms
I. dvi
main base for numeral nominal composition & derivation, in:

numeral dve (& duve) two: nom. acc.; dve (Snp.p.107; Iti.98; Ja.i.150; Ja.iv.137 etc.) & (in verse); duve (Snp.896, Snp.1001); gen. dat. dvinnaṃ (Iti.39, Iti.40, Iti.98; Ja.ii.154) instr. dvīhi (Ja.i.87: variant reading dīhi; 151; ii.153); loc. dvīsu (Ja.i.203; Pva.47) & duvesu (Vv.41#2).

 as numeral base: sahassa 2000 (see A I. 2^{b}) Ja.i.57; Vva.261; Pva.74; also in dvittā and adv. dvikkhattuṃ twice & dvidhā in two parts
 as nominal base: (r)āvaṭṭa Sk. dviḥ cp. Lat. bis turning twice SN.i.32; ja “twice born,” i.e. a bird Ja.i.152 (gaṇā) jātin one who is born twice, i.e. a brāhmaṇa Thig.430 (Thaga.269 = brahmajātin); tālamatta of the size of 2 palms Dhpa.ii.62; pad [Sk. dvipad, Lat. bipes, Gr.δίπους etc.] a biped, man SN.i.6; pala twofold Vism.339 pādaka = dvipad Vin.ii.110; bandhu having two friends Ja.vi.281; rattatiratta two or three nights Vin.iv.16; also in dvīha two days (q.v.).

as diaeretic form duvi˚ja (cp. dija) “growing again” i.e. a tooth Ja.v.156.

as contracted form di˚(y)aḍḍha one and a half (lit. the second half, cp. Ger. anderthalb) Dhp.235; Ja.i.72 (diyaḍḍhayojanasatika 150 y. long or high etc.) Ja.i.202; Ja.iv.293 (˚yāma); Dhpa.i.395; DNa.i.17; Mil.243 Mil.272; Dhsa.12; guṇa twofold, double Vin.i.289; Snp.714; Ja.v.309; Mil.84; Dhpa.ii.6; Vva.63, Vva.120; ja (cp. dvija, duvija)
 “twiceborn,” a bird SN.i.224; Snp.1134 (d. vuccati pakkhī Cnd.296); Ja.i.152, Ja.i.203 Ja.ii.205; Ja.iv.347; Ja.v.157; Pv.ii.12#4; Vv.35#8 (cp. Vva.178) Mil.295
 a brahmin Thaga.70, Thaga.73; jivha “twotongued,” i.e. a snake (cp. du˚) Ja.iii.347; pad (pada orpa) a biped (cp. dvi˚) AN.i.22; AN.v.21; Snp.83 (dipaduttama), Snp.995 (id.) Snp.998; Dhp.273; pādaka = ˚pad Thag.453 = Snp.205.

as sec. cpd. form (with guṇa) dve˚; (and de˚) caturaṅga twice fourfoldeightfold Thag.520 (˚gāmin); patha a “double” path, a border path, the boundary between two villages Vv.53#17 (sīmantikapatha Vva.241); piccha having two tailfeathers Ja.v.341 (cp. de˚); pitika having two feathers Ja.v.424 bhāva doubling kacc. 21; māsika two months old Pv.i.6#7; vācika pronouncing (only) two words, viz Buddha & Dhamma (cp. tevācika, saying the whole saraṇaformula), Vin.i.4; Ja.i.81; sattaratta twice seven nights, a fortnight [cp. Sk. dvisapta] Ja.vi.230
■ See also der. fr. numer. adv. dvidhā, viz. dvejjha (& dejjha) dvedhā˚, dveḷhaka. 
as nounderivation dvaya a dyad (q.v.).
II. du
reduced base in numeral and nominal compound & der^{n}:
(v)addhato from both sides (a distorted form of dubhato q.v.) Vv.64#19 (= dubhato Vva.281); (v)aṅgika consisting of two parts Dhs.163; (v)aṅgula & dvaṅgula; two fingerbreadths or depths, two inches long, implying a minimum measure (see above AN I.2^{a}) Vin.ii.107 Vin.iv.262; usually in cpds
■ kappa the 2 inch rule, i.e. a rule extending the allotted time for the morning meal to 2 inches of shadow after mid day Vin.ii.294 Vin.ii.306 pannā wisdom of 2 fingerbreadths, i.e. that of a woman SN.i.129 = Thig.60 (dvanguli˚, at Thaga.66 as ˚saññā); buddhika = ˚paññā Vva.96; jivha twotongued (cp. di˚); a snake Ja.iv.330; Ja.v.82, Ja.v.425; paṭṭa “double cloth” (Hind. dupaṭṭā; Kanarese dupaṭa duppaṭa; Tamil tuppaṭṭā a cloak consisting of two cloths joined together, see Kern,
Toevoegselen
i.179) Ja.i.119; Ja.iv.114, Ja.iv.379 (ratta˚); Dhpa.i.249 (suratta˚) Dhpa.iii.419 (˚cīvarā); matta (about), Dhpa.iii.2 in measure Mil.82 māsika 2 months old or growing for 2 months (of hair Vin.ii.107; vagga consisting of two Vin.i.58; vassa 2 years old Vin.i.59; vidha twofold, instr. duvidhena MN.iii.45 sq.; etc
■ Derivations from du˚ see sep. under duka (dyad), dutiya (the second), & the contamination forms; dubha (to) & dubhaya (for ubha & ubhaya).
III. dvā
(& reduced; dva), base in numeral compound only.
dvatikkhattuṃ two or three times Ja.i.506; DNa.i.133, DNa.i.264; Dhpa.iv.38; dvādasa twelve (on meaning of this & foll. numerals see above AN II. & III.) Ja.iii.80 Ja.vi.116; Dhpa.i.88; Dhpa.iii.210; Vva.156, Vva.247 etc.; yojanika Ja.i.125; Ja.iv.499; dvāvīsati (22) Vva.139; dvattiṃsa (32) Kp ii. (˚ākāra the 32 constituents of the body) Dhpa.ii.88; Vva.39 etc.; dvācattālīsa (42) Cnd.15 Vism.82; dvāsaṭṭhi (Cnd.271#iii. & dvaṭṭhi (62) DN.i.54; SN.iii.211; DNa.i.162); dvānavuti (92) Pva.19, Pva.21
Note. A singular case of dva as adv. = twice is in dvâhaṃ Snp.1116.
Sk. dvi, dva etc. Bases:
(I) dvi = Sk. dvi in dvipad = Lat. bipēs (fr. dṷipēs), Ags. twiféte; dvidant = bidens. Reduced to di (see B I.^{4}) as in Gr. δδιπους (= dipad), Lat diennium & pref. dis(cp. Goth. twis asunder, Ogh zwisk between)
(II) du (= dvi in reduced grade, cp Lat. duplex, dubius etc.)
(III) dvā (& dva) = Sk dvāu, dvā, f. nt. dve (declined as dual, but the P (plural) inflexion from base I. see B I^{1}); Gr. δύω, Lat duo; Oir. dāu, dā, f. dī; Goth. twai, f. twōs; Ags. twā (= E. two); Ohg. zwēne, zwō zwei. Also in cpd num. dvadaśa twelve = Gr. δ(* ̔́)ώδεκα = Lat. duodecim