Roof
Etymology

Old English hrof 'roof, ceiling, top, summit; heaven, sky', also figuratively, 'highest point of something', from Proto-Germanic * khrofam (cf. Dutch roef 'deckhouse, cabin, coffin-lid', Middle High German rof 'penthouse', Old Norse hrof 'boat shed'). There are no apparent connections outside the Germanic family. "English alone has retained the word in a general sense, for which the other languages use forms corresponding to OE. þæc thatch".
oulipo:avoid_letter[t], punctuation:no_comma, detectable_content:postscript