doorn.

Etymology: Old English duru, feminine u-stem, not found elsewhere in Germanic, but from the same base dur-, as the equivalent words in the other languages: compare Old High German turi, an original plural, which became a feminine singular, Middle High German tur, German thür(e, Old Dutch duri, plural (Middle Dutch döre, dore, Dutch deur, feminine singular), Old Saxon duri, Old Norse dyrr feminine plural (and noun), Swedish dörr (feminine), Danish dör; also Gothic daurôns plural weak feminine Old English had also dor neuter, plural doru, large door, gate = Gothic daur, Old Saxon dor, Old High German tor, German thor gate. The same stem dhur-, dhwâr- appears in Sanskrit dvṛ, dwâr, Greek θύρα, Latin fores. The two Old English types duru, and dor appear to have been mixed in Middle English, where, beside dure and dor, are also found dur and dore. Dore prevailed in 16th cent., and is found as late as 1684; door appeared in 16th cent., and at length supplanted dore in writing, though now pronounced like the latter. The spelling door points to an earlier pronunciation with ū or ū from Middle English close ō , which is further attested by Scots dure /dør/ (also in Cath. Angl. 1483), and is considered by Luick as a northern lengthening of Old English u . The current pronunciation may be a retention of that evidenced for 16th cent. dore by quot. 1597 at sense 1aβ. ; but it may also be a more recent modification of /dʊə(r)/, as in the case of floor, and some pronunciations of moor, poor.