"provide a roof for, cover with a roof," early 15c., rofen, from roof (n.). Related: Roofed; roofing.

"outer upper covering of a house or other building," Middle English rof, from Old English hrof "roof," also "ceiling," hence figuratively "highest point, top, summit" also "heaven, the sky;" from Proto-Germanic *khrofam (source also of Old Frisian rhoof "roof," Middle Dutch roof, rouf "cover, roof," Dutch roef "deckhouse, cabin, coffin-lid," Middle High German rof "penthouse," Old Norse hrof "boat shed").

No apparent connections outside Germanic. "English alone has retained the word in a general sense, for which the other languages use forms corresponding to OE. þæc thatch" [OED]. Meaning "top of a carriage, etc." is by 1706. The meaning "upper part of the mouth, the hard palate" was in late Old English (hrof ðæs muðes). To raise the roof "create an uproar" is attested from 1860, originally in U.S. Southern dialect.

1540s and thereafter in various senses in reference to things (landforms, oysters, etc.) shaped like a saddle, from saddle (n.) + back (n.). Related: Saddle-backed.

also roof-line, "the outline or silhouette of a roof or range of roofs," by 1829, from roof (n.) + line (n.).

also roof-top, "the top of a roof," 1610s, from roof (n.) + top (n.1). As an adjective by 1935 in reference to anything situated on top of a building.

Old English þæc "roof, thatch, cover of a building," from Proto-Germanic *thakam (source also of Old Norse þak, Old Frisian thek, Swedish tak, Danish tag, Middle Dutch, Dutch dak "roof," Old High German dah "covering, cover," German Dach "roof"), from PIE root *(s)teg- "to cover."

"to form with a vault or arched roof," late 14c., from Old French vaulter, volter, from voute "arch, vaulted roof" (see vault (n.1)). Related: Vaulted; vaulting.

Proto-Indo-European root meaning "to cover," especially with a roof. It forms all or part of: deck (n.) "covering over part of a ship;" deck (v.) "adorn;" deckle; detect; integument; protect; protection; stegosaurus; tegular; tegument; thatch; thug; tile; Tuileries.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit sthag- "cover, conceal, hide;" Greek stegein "to cover," stegos "a roof;" Latin tegere "to cover," tegula "tile;" Lithuanian stėgti "to roof;" Old Norse þekja, Old English þeccan "thatch;" Dutch dekken, German decken "to cover, put under roof;" Irish tuigiur "cover," tech "house;" Welsh toi "thatch, roof," ty "house."

"one who makes or repairs roofs," 1835, agent noun from roof (v.).

type of plant-eating dinosaur, 1892, from Modern Latin order name Stegosauria (O.C. Marsh, 1877), from Greek stegos "a roof" (related to stege "covering," stegein "to cover," from PIE root *(s)teg- "to cover" + -saurus. The back-armor plates in the fossilized remains look like roof tiles.