In this post we’re looking into words for flour and related things in Celtic languages.

Proto-Celtic	*mlātos = flour
Gaulish	*blatos = flour
Proto-Brythonic	*blọd = flour
Middle Welsh (Kymraec)	blawd, blaỼt = flour
Welsh (Cymraeg)	blawd = flour, meal, powder blawdaidd = mealy, floury, friable blodiaf, blawdiaf, blawdio = to grind into meal, produce flour, become powdery, turn to dust, sprinkle (with) flour blodiwr, blawdiwr = flour or meal merchant
Old Cornish	blot = flour, meal
Middle Cornish (Cernewec)	blot, blês = flour, meal
Cornish (Kernewek)	bleus = flour bleus hesken = sawdust bleus leun = wholemeal bleusa = to flour
Old Breton (Brethonoc)	blot = flour
Middle Breton (Brezonec)	bleut = flour, powder
Breton (Brezhoneg)	bleud = flour, powder bleudañ = to flour bleudek = floury bleud brazed = wholemeal flour bleud goellet = self-raising flour bleud gwinizh = wheat flour

Etymology: from the Proto-Indo-European *ml̥h₂-tó-s, from *melh₂- (to crush, grind) [source]. Words from the same root include melancholy and melanin in English, and μελανός (melanós – black, dark, blue, bruised) in Greek [source].

Old Irish (Góidelc)	men = flour
Middle Irish (Gaoidhealg)	men, min = flour, meal, fine powder, dust
Irish (Gaeilge)	min [ˈmʲɪnʲ/ˈmʲɨ̞nʲ] = meal; powedered matter min choirce = oatmeal min chruithneachta = wheatmeal min sáibh = sawdust
Scottish Gaelic (Gàidhlig)	min [min] = flour, meal, grounds, filings min-fhlùir = flour min-eòrna = barley flour/meal min-sheagail = rye flour min-chruithneachd = wheat flour muileann-mine = flour mill
Manx (Gaelg)	meinn = meal meinn chorkey = oatmeal meinn churnaght = wheatmeal flour meinn hoggyl = rye meal meinn oarn = barley meal meinn saaue = sawdust

Etymology: unknown

Middle Welsh (Kymraec)	peyllyeyt, peillit = flour
Welsh (Cymraeg)	paill = pollen, flour peill(i)aid = flour, fine flour, wheat flour, white flour, powder peilliaid gwenith = (fine) wheat flour peilliaid haidd = barley flour peilliaid rhyg = rye flour

Etymology: from the Latin pollen (fine flower, powder, dust), from the Proto-Indo-European *pel- (flour, dust) [source].

Words from the same roots, via the Latin pulvis (dust, powder, ashes), include polve (dust, ashes) in Italian, polvo (dust, powder) in Spanish, poussière (dust) in French, and pulverise (to render into dust or powder) in English [source].

Irish (Gaeilge)	plúr [pˠlˠuːɾˠ] = flour, flower plúr geal = white flour plúr cruithneachta = wheaten flour plúrach = floury, farinaceous; flower-like, pretty plúraigh = to effloresce plúróg = pretty girl plúrscoth = choicest flower, pick, choice plúrú = efflorescence
Scottish Gaelic (Gàidhlig)	flùr [fl̪ˠuːr] = flour flùr lom = plain flour flùr-éirigh = self-raising flour
Manx (Gaelg)	flooyr = flour flooyr churnaght = wheaten flour grine-flooyr = cornflour
Middle Welsh (Kymraec)	fflwr = flour
Welsh (Cymraeg)	fflŵr [fluːr], fflowr = flour (in South Wales) fflŵr can = wheat flour

Etymology: from the Anglo-Norman flur (flower), from the Old French flor (flower), from the Latin flōrem (flower), from flōs (flower, blossom), from Proto-Italic *flōs (flower, blossom), from Proto-Indo-European *bʰleh₃- (flower, blossom) [source].

Words from the same PIE roots include flour, flower, flora, blossom and bloom in English, blé (flour) and fleur (flower) in French, and blat (wheat) in Catalan [source].

Words marked with a * are reconstructions.

Sources: Wiktionary, Am Faclair Beag, Online Manx Dictionary, Teanglann.ie, eDIL – Electronic Dictionary of the Irish Language, In Dúil Bélrai English – Old Irish glossary, Geiriadur Prifysgol Cymru, Gerlyver Kernewek, Dictionaire Favereau, TermOfis, English – ProtoCeltic WordList (PDF), Etymological Dictionary Of Proto Celtic