"dial for showing the hours by the light of the moon," 1680s, from moon (n.) + dial (n.).
Entries linking to moon-dial
moon n.
"heavenly body which revolves about the earth monthly," Middle English mone, from Old English mona, from Proto-Germanic *menon- (source also of Old Saxon and Old High German mano, Old Frisian mona, Old Norse mani, Danish maane, Dutch maan, German Mond, Gothic mena "moon"), from PIE *me(n)ses- "moon, month" (source also of Sanskrit masah "moon, month;" Avestan ma, Persian mah, Armenian mis "month;" Greek mene "moon," men "month;" Latin mensis "month;" Old Church Slavonic meseci, Lithuanian mėnesis "moon, month;" Old Irish mi, Welsh mis, Breton miz "month"), from root *me- (2) "to measure" in reference to the moon's phases as an ancient and universal measure of time.
A masculine noun in Old English. In Greek, Italic, Celtic, and Armenian the cognate words now mean only "month." Greek selēnē (Lesbian selanna) is from selas "light, brightness (of heavenly bodies)." Old Norse also had tungl "moon," ("replacing mani in prose" - Buck), evidently an older Germanic word for "heavenly body," cognate with Gothic tuggl, Old English tungol "heavenly body, constellation," of unknown origin or connection. Hence Old Norse tunglfylling "lunation," tunglœrr "lunatic" (adj.).
Extended 1665 to satellites of other planets. Typical of a place impossible to reach or a thing impossible to obtain, by 1590s. Meaning "a month, the period of the revolution of the moon about the earth" is from late 14c.
To shoot the moon "leave without paying rent" is British slang from c. 1823 (see shoot (v.)); the card-playing sense perhaps was influenced by gambler's shoot the works (1922) "go for broke" in shooting dice. The moon race and the U.S. space program of the 1960s inspired a number of coinages, including, from those skeptical of the benefits to be gained, moondoggle (based on boondoggle). The man in the moon "fancied semblance of a man seen in the disk of the full moon" is mentioned since early 14c.; he carries a bundle of thorn-twigs and is accompanied by a dog. Some Japanese, however, see a rice-cake-making rabbit in the moon. The old moon in the new moon's arms (1727) is the appearance of the moon in the first quarter, in which the whole orb is faintly visible by earthshine.
dial n.
early 15c., "sundial, instrument for indicating the hour of the day by means of a shadow thrown upon a graduated surface," earlier "dial of a compass" (mid-14c.), from Old French dyal, apparently from Medieval Latin dialis "daily," from Latin dies "day," from PIE root *dyeu- "to shine." The word perhaps was abstracted from a phrase such as Medieval Latin rota dialis "daily wheel."
It evolved to mean any round plate or face over which a pointer moves to indicate something about the machinery to which it is attached. Sense of "face of a clock (or later a watch), upon which hours and minutes are marked and over which the hands move" is from mid-15c.
Telephone sense "circular plate marked with numbers and letters which can be rotated to establish connection" is from 1879, which led to dial tone (1921), "the signal to begin dialing." Dial-plate is attested from 1680s.