However, LUNCH, being the mid-day meal, much more likely comes from:
launags (Latv.) - afternoon snack;
lȭnag (Livonian) - south-east; lȭnagist (Livonian) - mid-day meal;
lõuna (Est.) - south and mid-day meal;
lounas (Fin.) - south-west and mid-day meal;
lõunad, lõunaz (Votic) - south and mid-day meal;
lounad, loune(d) (Izhorian) - south and mid-day meal;
lounat (Karelian) - evening and main meal;
lun (Komi) - day and daylight;
lun-aǯ́e (Udmurt) - during the day.
Why should comparisons be made to the Baltic and Finno-Ugric languages for the rare word LUNCH (found in English, not used in any other Germanic language, and very clumsily explained by OED (Oхford Etym. Dictionary), as quoted above)?
To answer this, one should distance from the 'Indo-Germanist' hypothesis: https://new-etymology.livejournal.com/20922.html (which arbitrarily decided that Finno-Ugric languages are 'new' to Europe).
One should rather re-read what Tacitus said 20 centuries ago about the language of Aestii (the people of the Eastern coast of the Baltic Sea: https://new-etymology.livejournal.com/22868.html ): Tacitus described the language of Aestii as closer to that spoken in Britain (Tacitus, Germania).
And is the language of Aestii not related to that of Estonians? Prof. Birger Nerman of Sweden, a specialist on Scandinavian and Baltic history, already a century ago concluded: "...I do not find any indications that the nation Aestii, named by Tacitus as dwelling in Ost-Balticum, are not Estonians. There is no evidence whatever against this fact; also in the 6th century Jordanes lists the Estonians as living along the coast of the Baltic sea, and Alfred reports that Estonia is very large." (Nerman, 1929).
As gathered by Andres Pääbo: 'The old linguistic theory on the origins of Finno-Ugric languages, in describing their origins in a tight location near the Ural mountains, has done the world of scholarship a great disservice. For over a century scholars have completely ignored the Finno-Ugric languages in investigations of prehistoric Europe simply because they have been told they were not there, but in the east.' A.Pääbo: LANGUAGES DISCUSSION: ORIGINS AND NATURE OF THE LANGUAGES OF THE BOAT PEOPLES, TRADITIONALLY KNOWN AS "FINNO-UGRIC" http://www.paabo.ca/uirala/FinnoUgricbkgd.html
The connection of 'day, daylight, clear sky' (like in Komi, Udmurt lun), and 'south' (like in Est. lõuna), and 'lunch' (like in Est. lõuna) may be similarly observed in:
✔ югъ [yug] (Old Georgian), йагъ [yag] (Megrelian), egun (Basque) – day;
ég (Hung.) - sky, heaven, to burn, to flame;
aeg, aja (Est.) - time, epoche, also day (see for other related Finnic words: http://www.eki.ee/dict/ety/index.cgi?Q=aeg&F=M&C06=et )
Compare also to the four Yugas (or ages) the world went through as part of a 'cycle of yugas' described in the Sanskrit scriptures, each followed by 'the end of the light' cataclisms.
юг [yug] (Rus., Bulg.), jug (Albanian, Bosnian, Slovenian, Croatian), југ (Makedonian, Serbian), juh (Slovakian), jih (Szech) - south; южный [yuzhny] (Rus.) - southern;
egu, hego (Basque) - south;
ужин [uzhin] (Rus.), у́жина, ю́жина [uzhina, juzhina] (Old Bulgarian), у̏жина [uzhina] (Old Serbian), júžinа (Old Slovenian), juzyna (Old Polish), Jause (Old German dialect) - dinner, initially midday meal; uzsonna (Hung.) - snack;
[Spoiler (click to open)]✔ [di] (Sumerian) - to shine; de, di, didal (Sumerian) - flame;
dies, diē, diī (Lat.), dia (Sp.) - day, daylight (Eng.);
день [den'] (Ukr., Rus.), дзень [dzen'] (Belorussian), dzień (Polish), 天 [Tiān] (Chinese) - day;
таң [tang] (Kazakh), dan (Azeri), tan (Turkish) - dawn (Eng.);
täna (Est.), tänään (Fin.), туннэ [tunne] (Udmurt) - today;
taevas (Est.), taivas (Fin.) - sky (see for other related Finnic words: http://www.eki.ee/dict/ety/index.cgi?Q=taevas&F=M&C06=et );
deas (Scottish), theas (Irish) - south;
meridies (Lat.), mediodía (Sp.) – south (literally, midday);
пiвдень [pivden] (Ukr.), поўдзень [poudzen'] (Belorussian), południe (Polish) – south (literally, midday);
တောင် [taung] (Burma) - south;
dine, dinner (Eng.) - to eat lunch, lunch;
полдник [poldnik] (Rus.), полуденок [poludenok] (Ukr.) - midday meal, literally.
✔ dal (Sumerian) - fire; de, di, didal (Sumerian) - flame;
tuli, gen. tule (Est.), tu’ļ (Livic), tuli (Fin., Votic, Izhorian, Karelian), tuľi (Chud'), tuli, tuľ (Vepssian), tol (Erzia, Miksha), tul (Mari), ti̮l (Udmurt), ti̮v (Komi), tu (Nenets, Enets), tui (Nganasan), tǖ- (Sekulpian), tuj (Matori), tűz (Hung.), dolla (Saami) - fire;
dalla, dal, daal (Sumerian) - midday;
dél (Hung.) - south, midday; déli (Hung.) – southern;
✔ giorno (It.) - day;
mezzogiorno (It.) – south (literally, midday);
✔ noon (Eng.) - midday; nun, nunal (Udmurt) - day;
南 [Nán] (Chinese), 남 [naam] (Korean) - south.