Etymology: < (i) Anglo-Norman ruwine, rewynne, Anglo-Norman and Middle French ruine, ruyne (French ruine ) devastation, destruction (especially of an object) (1155), downfall or decay of a person or society (c1175, originally with reference to the Fall of the Angels), headlong fall, action of falling down (early 13th cent. or earlier, originally with reference to a landslide), collapsed remains of a building (c1213), state or condition of a person who or society which has suffered decay or downfall (late 14th cent.; the sense ‘cause of destruction or downfall’ is apparently not paralleled in French until later: late 16th cent.), and its etymon (ii) classical Latin ruīna headlong rush, headlong fall, downward plunge, collapse (of a building), fallen mass of debris, (usually plural) collapsed remains of a particular building or town, destruction of hopes or position, collapse, downfall, source of destruction < ruere rue v.² + -īna -ine suffix⁴. Compare Old Occitan ronha, ruina (14th cent.), Catalan ruïna (1272), Spanish ruina (late 14th cent. as †ruyna), Portuguese ruína (1623), Italian rovina (c1300; a1292 as †ruina).The Latin noun was also borrowed into other Germanic languages, in some cases via French. Compare Middle Dutch ruine (Dutch ruïne ), German Ruine (feminine) ruined building (16th cent.), Ruin (masculine) collapse, downfall, state or condition of collapse (17th cent.; via French), Swedish ruin (1621; also †ruine ), early modern Danish, Danish ruin . The following example has been taken by some (see e.g. Middle Eng. Dict. at ruīn(e n.) to show a considerably earlier occurrence of this word (in sense 3a):c1175 ( Homily (Bodl. 343) in S. Irvine Old Eng. Homilies (1993) 200 Eac þa heahȝæ torræs and clifæs þe heaȝæ stondæþ ofer alle oþre eorðæ, heo eac þe mare rune nimæð [OE Vercelli ful heardlice hrioseð; L. grauiori casu procumbunt] ȝyf heo feringæ to eorðe fællæþ.However, the form rune is unparalleled, and is better explained as a scribal error for rure n. With in ruin, into ruin at sense 1 compare Anglo-Norman and Middle French, French en ruine (beginning of the 15th cent. or earlier). With to ruin at sense 1 compare Anglo-Norman and Middle French, French à ruine (13th–14th cent. or earlier). With to fall to ruin compare Middle French enchoir en ruine (late 14th cent.), dechoir en ruine (early 15th cent.), Middle French, French tomber en ruine (1549).

Etymology: Probably partly < (i) Middle French ruyner , Middle French, French ruiner to fall, to fall in ruins (end of the 13th cent. in Old French), to cause to lose wealth or other resources (c1350; 1587 used reflexively), to reduce to ruins (1534), to destroy, reduce to nothing (1538), to overturn, falsify (an idea, etc.) (1580), and its etymon (ii) post-classical Latin ruinare to fall headlong, to fall into ruins (6th cent.), to destroy (from 7th cent. in British sources), and partly (iii) < ruin n. Compare ruinate v.Compare Old Occitan ruinar (16th cent.), Spanish (rare) ruinar (1555), Portuguese (rare) ruinar, Italian rovinare (early 14th cent.; late 13th cent. as †ruinare, †ruvinare), and (with added prefix) Middle French aruiner (1412), Spanish arruinar (1547), Portuguese arruinar (14th cent. as †arruinhar). Compare also Dutch ruïneeren (1566). All of these parallel verbs show a similar range of meanings.