ratti : [f.] night.

A.P. Buddhadatta Mahathera, Concise Pali-English and English-Pali Dictionary [available as digital version from Metta Net, Sri Lanka]

Ratti (f.) [Vedic rātrī & later Sk. rātri. -- Idg *lādh as in Gr. lh/qw=Lat. lateo to hide; Sk rāhu dark demon; also Gr. *lhtw/ (=Lat. Latona) Goddess of night; Mhg. luoder insidiousness; cp. further Gr. lanqa/nw to be hidden, lh/qh oblivion (E. lethargy). -- The by -- form of ratti is ratta2] night D i.47 (dosinā). gen. sg. ratyā (for *rattiyā) Th 1, 517; Sn 710 (vivasane=ratti -- samatikkame SnA 496); J vi.491. abl. sg. rattiyā in phrases abhikkantāya r. at the waning of night D ii.220; Vin i.26; S i.16; M i.143; & pabhātāya r. when night grew light, i. e. dawn J i.81, 500. instr. pl. rattīsu Vin i.288 (hemantikāsu r.). A loc. ratyā (for *rātryām) and a nom. pl. ratyo (for *rātryaḥ) is given by Geiger, P.Gr. § 583. -- Very often combd with and opp. to diva in foll. combns: rattin -- diva [cp. BSk. rātrindiva=Gr. nuxqh/meron, AvŚ i.274, 278; ii.176; Divy 124] a day & a night (something like our "24 hours"), in phrase dasa rattindivā a decade of n. & d. (i. e. a 10 -- day week) A v.85 sq.; adverbially satta -- rattin -- divaŋ a week DhA i.108. As adv. in acc. sg.: rattin -- divaŋ night and day A iii.57; Sn 507, 1142; It 93; J i.30; or rattiñ ca divañ ca Nd2 538, or rattiŋ opposed to adv. divā by night -- by day M i.143; PvA 43. -- Other cases as adv.: acc. ekarattiŋ one night J i.62; Pv ii.97; PvA 42; taŋ rattiŋ that night Mhvs 4, 38; imaŋ r. this night M i.143; yañ car. . . . yañ car. . . . etasmiŋ antare in between yon night and yon night It 121; rattiŋ at night Miln 42; rattiŋ rattiŋ night after night Mhvs 30, 16. -- gen. rattiyā ca divasassa ca by n. & by day S ii.95. -- loc.rattiyañ by night VvA 130, 315 (aḍḍha˚ at midnight); PvA 22; and ratto in phrase divā ca ratto ca Sn 223; Th 2, 312; Dh 296; Vv 315; 8432; S i.33.
   -- khaya the wane of night J i.19. -- cāra (sabba˚) allnight wandering S i.201 (trsl. "festival"). -- cheda interruption of the probationary period (t. t.) Vinii.34 (three such: sahavāsa, vippavāsa, anārocanā). -- dhūmāyanā smouldering at night Vism 107 (v. l. dhūp˚), combd with divā -- pajjalanā, cp. M i.143: ayaŋ vammīko rattiŋ dhūmāyati divā pajjalati. -- pariyanta limitation of the probationary period (t. t.) Vin ii.59. -- bhāga night -- time J iii.43 (˚bhāge); Miln 18 (˚bhāgena). -- bhojana eating at night M i.473; DA i.77. -- samaya night -- time, only in loc. aḍḍha -- ratti -- samaye at midnight VvA 255; PvA 155.

Pali-English Dictionary, TW Rhys Davids, William Stede,