What's the "een" in Halloween?
early 14c., from stem of Old French areer "to put in order," from Vulgar Latin *ar-redare (source of Italian arredare), from Latin ad- "to" (see ad-) + Frankish *ræd- "ready" or some cognate Germanic source, from Proto-Germanic *raidjan "to place in order" (cf. Gothic garadis, Old English geræde "ready;" see ready (adj.)). Related: Arrayed; arraying.
mid-14c., "order, arrangement," from Anglo-French arrai, Old French aroi, from areer (see array (v.)).