Where does “one-way mirror” come from?

one-way mirror (English) comes from English mirror, from Middle English mirour, from Old French mireor, from Old French mirer, from Latin mīror, from Latin mīrus, from Proto-Italic smeiros, from Proto-Indo-European sméyros — to smile; to smear, stroke, wipe, rub; to be...

one-way mirror (English): A mirror reflecting images on one side and...

Definitions

  1. A mirror reflecting images on one side and...

Ancestry of “one-way mirror”, step by step

one-way mirror traces back through two separate lines of ancestry.

via English mirror

StepLanguageWordMeaning
1EnglishmirrorA smooth surface, usually made of glass with...
2Middle EnglishmirourA mirror, looking-glass, or other reflective...
3Old Frenchmireormirror; a typical example
4Old Frenchmirerto look at; to watch
5Latinmīrorto be astonished at, marvel at, admire, be amazed at, wonder at
6Latinmīruswonderful, marvelous, amazing, surprising, miraculous
7Proto-Italicsmeiros
8Proto-Indo-Europeansméyroslaughing, smiling
9Proto-Indo-Europeansmey-to smile; to smear, stroke, wipe, rub; to be...

via English one-way

StepLanguageWordMeaning
1Englishone-wayAllowing movement in only one direction;...
2EnglishOneThe number represented by the Arabic numeral 1; the numerical value equal to that cardinal number
3Middle Englishonon, in; on; Alternative form of oon
4Old Englishonon, in, at, among; from
5Proto-West Germanicanaon
6Proto-Germanic*an
7Proto-Germanicanaon, at; on, onto; ana
8Proto-Indo-Europeanh₂en-on, onto
Every word from Proto-Indo-European smey-Every word from Proto-Indo-European sméyrosEvery word from Proto-Italic smeiros
one-way mirror — Etymology, Origin & Word History | Etymology Explorer