Etymology
Advertisement
mullion (n.)

in architecture, "a vertical column between the lights of a window or screen," 1560s, metathesis of Middle English moyniel (early 14c.), from Anglo-French moinel, noun use of moienel (adj.) "middle," from Old French meien "intermediate, mean" (see mean (adj.)). Related: Mullioned.

Related entries & more 
Advertisement
defenestration (n.)

1620, "the action of throwing out of a window," from Latin fenestra "window." A word invented for one incident: the "Defenestration of Prague," May 21, 1618, when two Catholic deputies to the Bohemian national assembly and a secretary were tossed out the window of the castle of Hradschin by Protestant radicals (the pair landed in a trash heap and survived). It marked the start of the Thirty Years' War.

The extraordinary chance which had saved three lives was a holy miracle or a comic accident according to the religion of the beholder .... Murder or no murder, the coup d'état was complete, and since Thurn had overruled many of his supporters in demanding death it was well for the conscience of his allies that a pile of mouldering filth in the courtyard of the Hradschin had made soft falling for the governors. [Cicely Veronica Wedgwood, "The Thirty Years War," 1938]

Some linguists link fenestra with Greek verb phainein "to show;" others see in it an Etruscan borrowing, based on the suffix -(s)tra, as in Latin loan-words aplustre "the carved stern of a ship with its ornaments," genista "the plant broom," lanista "trainer of gladiators." Related: Defenestrate (1915); defenestrated (1620).

Related entries & more 
tracery (n.)
mid-15c., "a place for drawing," formed in English from trace (v.) + -ery. Architectural sense, in reference to intersecting rib work in the upper part of a gothic window, is attested from 1660s. "Introduced by Wren, who described it as a masons' term" [Weekley].
Related entries & more 
squeegee (n.)

"wooden scraping instrument with a rubber blade," 1844, a nautical word originally, earlier squilgee, squillagee (Dana, 1840), "a small swab made of untwisted yarns. Figuratively, a lazy mean fellow" [Smythe], perhaps from squeege "to press" (1782), an alteration of squeeze (v.). Later in photography, then window-washing.

Related entries & more 
undo (v.)
Old English undon "to unfasten and open" (a window or door), "to unfasten by releasing from a fixed position; to cancel, discharge, abrogate, reverse what has been done, put back in a former condition; bring to ruin, destroy," from un- (2) "opposite of" + do (v.). Related: Undone; undoing.
Related entries & more 
Advertisement
display (n.)

1580s, "description," a sense now obsolete, from display (v.). Meaning "exhibition, a spreading of anything to the view," commonly with a suggestion of ostentation or striving for effect, is from 1680s. Meaning "presentation of electronic signals on a screen" is from 1945 in reference to radar, by 1960 of computers. Display-window is attested by 1893.

Related entries & more 
glazier (n.)
"one who fits window glass into frames," early 15c. variant of late 14c. glasier (late 13c. as a surname, glasyer, from glass (v.) + -er (1). Influenced by French words in -ier. Alternative glazer recorded from c. 1400 as "one who applies coatings to earthenware."
Related entries & more 
awning (n.)

"movable roof-like covering of canvas for a window, etc., as a protection from the sun's rays," 1624, origin uncertain (first recorded use is by Capt. John Smith), perhaps from French auvans, plural of auvent "a sloping roof," "itself of doubtful etym[ology]" (OED). A nautical term only until sense of "cover for windows or porch" emerged 1852.

Related entries & more 
loophole (n.)
also loop-hole, mid-15c., from hole (n.). + Middle English loupe "narrow window, slit-opening in a wall" for protection of archers while shooting, or for light and ventilation (c. 1300), which, along with Medieval Latin loupa, lobia probably is a specialized word from a continental Germanic source, such as Middle Dutch lupen "to watch, peer." Figurative sense of "outlet, means of escape" is from 1660s.
Related entries & more 
bay (n.2)
"opening in a wall," especially a space between two columns, late 14c. from Old French baee "opening, hole, gulf," noun use of fem. past participle of bayer "to gape, yawn," from Medieval Latin batare "gape," perhaps of imitative origin. Meaning "compartment for storage: is from 1550s. Somewhat confused with bay (n.1) "inlet of the sea," it is the bay in sick-bay and bay window (early 15c.).
Related entries & more 

Page 3