One of the commenters unversed in etymology had the following to say:
Is it just me or has no one ever noticed that dias for day is the feminine form of dios = god? Day is therefore a goddess, which makes sense if your ancestors were sun worshippers or alike. If one knows the Spanish language it would seem they would notice this.
They didn't notice it because it isn't true. The words "day" and "deity" don't come from the same source; any apparent similarity is a mere coincidence. Since they're cognate to "dias" and "dios" respectively, we can discuss the English words and still have something to say about the Spanish versions.
"Day" probably comes to us from the Indo-European "agh-". (How did the "d-" get shoved onto the beginning? Hard to say: some think that the actual source is instead "dheighw-", "to warm".) It's tempting to assume that Latin "dies" (about which more below) comes into play somehow, but the OED is adamant on this point: there is absolutely no etymological relationship whatever between the two. At any rate, from the IE source, whichever it be, we get not only "day" but "dawn", and also, enchantingly, "daisy", a contraction of "day's eye".
"Deity", on the other hand, is definitively from IE "deiw-", "to shine". This also leads, sensibly enough, to "divinity", French "adieu", and Latin "dies", which means "day" and shows up in such occasionally seen phrases as "carpe diem", "seize the day", and "dies irae", "the day of wrath".
The French version of "day" is "jour", as in "soupe du jour", "soup of the day". From the Latin and French versions, we get, among other things, the paired words "diary" and "journal" in which you record the day's events; "dial", which denotes the hours of the day; "journey", originally a day's ride; and, marvelously, from "dies malus", "evil day", the word "dismal".