window

The English word for window is a Viking word, and a literal one. Old Norse vindauga, "wind-eye," came into English in the early Middle English period and displaced two older Anglo-Saxon compounds — ēag-þyrel ("eye-thirl," eye-hole) and ēag-duru ("eye-door"). The Norse compound won partly because the Norse settlers had glass earlier and named the thing in their own kitchens, partly because the metaphor is sharper. A window is not an eye-shaped hole. It is the place the wind comes through where the eye also goes.

The difference between the lost English compounds and the Norse one is in which noun is the head. In ēag-þyrel and ēag-duru, the eye is the head and the second element specifies the kind of eye-shaped thing: this kind of eye is a hole, that kind is a door. In vindauga, the eye is the modifier and the wind is the head. The thing is a wind-aperture; the eye-aspect is attached as a secondary function. The Anglo-Saxon compounds named the experience of the inhabitant looking out. The Norse compound named the architecture of the room admitting the air. When the Norse word displaced the English ones around 1200, the conceptual frame shifted from "what does this look like from inside" to "what does this do for the building." Vocabulary often carries a register the speakers no longer notice; this is one of those cases.

Two pieces of the older English vocabulary survived the displacement, and tracking them is its own small archaeology. Duru ("door") survived as the standard word for the larger aperture, the one a person walks through; the loss was only in the compound eye-door, not in the bare noun. Þyrel ("hole, perforation, opening") survived in exactly one compound — nostril, from Old English nosþyrel, "nose-thirl" — and is otherwise extinct in the modern language. The opacity is total: most English speakers have no idea that nostril is morphologically identical to the lost eyethurl, that both name an aperture in the face by the same Old English word for hole. The verb þyrlian ("to pierce, to bore through") survived a different way: the literal piercing became metaphorical, and a thrilling sensation became a metaphor for piercing emotion. Modern English thrill is the same word as the thirl in nostril. The two halves of one Old English word now live in completely different registers.

Underneath vindauga sit two of the deepest roots in Indo-European, and each one has a vast English family of its own. The first element, vindr ("wind"), comes from PIE *h₂weh₁-, "to blow." The Germanic branch took the present-participle form *h₂weh₁-nt- ("the blowing one") and froze it as a noun: Old English wind, Old Norse vindr, Old High German wint, Gothic winds. Across every branch of Germanic, the same word for the same thing. The Italic branch produced Latin ventus by the same participial morphology, giving English ventilate, vent, and (folk-etymologized) adventure, "what the wind brings." Latin also kept the bare verb vannere, "to winnow" — the agricultural action of throwing grain into the wind so the chaff blows away. The Greek branch gave the verb áēmi ("I blow"); the Sanskrit branch gave vāti ("it blows") and vāyu, the wind-god of the Vedas. Across the family the same image: the unbounded movement of air, named by the act of blowing rather than by the substance.

The second element, auga ("eye"), comes from PIE *h₃ekʷ-, one of the great perception-roots of Indo-European. The Latin branch produced oculus, the diminutive of an older eye-word, giving English an enormous cluster: ocular, oculist, binocular, monocle, inoculate (originally "to graft an eye-bud into a plant"), occult ("covered over, hidden from sight"). The Romance languages took the diminutive even further — Spanish ojo, French œil, Italian occhio are all oculus shortened through millennia of daily use. The Greek branch produced ōps ("eye, face") and its compounds — optic, optometry, synopsis ("a seeing-together"), autopsy ("a self-seeing"), Cyclops ("round-eye"), myopia ("closed-eye"). The Greek verb opsomai ("I will see") served as the suppletive future tense for the irregular verb of seeing. The Slavic branch gave Russian oko, the standard word for eye. The Indo-Iranian branch gave Sanskrit akṣi. The Germanic branch took the root with some unexplained vocalism into *augō, producing Old English ēage, Old Norse auga, German Auge, Dutch oog.

The window in the bones of the Norse compound is two of the deepest Indo-European roots fused into a single domestic noun. The wind comes in. The eye looks out. A room with a window is a room admitting both — the breathing of the outside air, the seeing of the outside world, sharing one aperture. Pre-glass, the two functions were truly the same: one hole, both jobs. Glass split them. The eye still goes through; the wind no longer does. The word, which is older than the glass, still says both. Glass added a function the architecture had never needed before — a barrier that admits one thing and refuses another. The word for the aperture is a word from before that selectivity, when the aperture meant: what is on the outside, let it in.

The modern extensions of window — the window of opportunity, the launch window, the browser window, the window into a person's mind — all keep something of the wind-eye sense. They name times or surfaces through which something passes that otherwise would not. The metaphor still relies on the pre-glass image: an aperture, briefly available, through which crossing happens. Closing the window means the crossing is no longer available; opening a window means the crossing has just become possible. The verb on glass is the same verb as on the wind — the verb of what the aperture lets through.