Origins of the word "hodie"

Question

Hodie is a Latin adverb meaning "today" or "at the present time". I am rather curious as to how this word developed.

Was it originally a compound of hōc and diē, which would be translated as "on this day"? That's the only theory I have so far; are there perhaps any definitive pieces of evidence on this topic?

Answer 1

As is often the case with things that seem obvious, the explanation of hodiē as a contraction of hōc + diē is actually problematic and hotly contested. One theory is that it is from the bare stem *ho-. Another that is from the old abl. sing. *hōd *diēd (with secondary shift of -ōdd- to -od-). The former seems to me more straightforward.

PS. Lewis and Short (1879) is hardly the last word on Latin etymology.

Answer 2

The simplest explanation is exactly as you suggested: hōc "this" + diē "day", in the ablative of time-when. This is what my old Latin textbook said, as well as Lewis and Short's dictionary:

hŏdĭē, adv. contr. from hoc die, on this day

Very similar derivations have happened in other languages:

• English "today" < Old English tō "at" + "day"
• German heute "today" < Old High German *hiu tagu "this day" (cf Tag)
• Dutch vandaag "today" < van "of" + daag "day"
• Attic Greek τήμερον "today" < *kyā- "this" (possibly the root of Latin cis) + ἡμέρα "day"

And Latin has similar words:

• prīdiē "on the day before" < Old Latin pri "before" (root of prior) + diē
• postrīdiē "on the day after" < posterō + diē

In comments on the other answer, brianpck provided some additional evidence. A fragment of Varro (number 11 here) mentions:

...et cum hodie dicimus, nihil aliud quam hoc die intelligitur.

(My translation:)

...and when we say "today", no other meaning except "on this day" is understood.

For a more modern and scholarly source, who probably did significantly more research than Varro, this article argues for the same etymology.

Answer 3

That's exactly right (though as a contraction), as a look at Lewis & Short shows:

hŏdĭē , adv. contr. from hoc die, on this day,

The English today actually developed in the same way:

today (adv.) Old English todæge, to dæge "on (this) day," from to "at, on" + dæge, dative of dæg "day."

Answer 4

1. Universal human laziness would have favored dropping the voiceless velar before the voiced dental. Under rapid speech, I don't think the /k/ sound would survive long. You don't always need a universal sound change rule for every change in a language. Some changes are bound to be random or unique. That's the second law of thermodynamics (which takes precedence over the rules of linguistics).
2. The tongue's location in the mouth for a dental sound is similar to where It is when /i/ or /e/ are articulated. Palletization may already have been underway in some dialects by the time "hoc" plus "die" became a compound word. It's not far-fetched to think that voiceless /k/ became voiced hard /g/ next to the voiced /d/, becoming palletized and then lost entirely in short order.
3. /K/ +/D/ is rare or impossible inside words in Latin, based on my limited experience. I wonder if, once it became a compound word, that this unusual combination of sounds ended up being dropped. If retained, it would be a marker of the border between two separate "words" rather than a possible internal consonant cluster of a proper Latin word. That would have been important to the native Latin listener. To conform with the rules governing consonant clusters within Latin words, the /k/ or the /d/ would have to be lost. Because "Day" is the dominant word-meaning unit, the /k/ sound of the subordinate "this" would have to be discarded by native speakers.
4. Perhaps it was a borrowing from a nearby But distinct latinate language in the early years of Rome. Perhaps that related language did have a rule for the loss of a voiceless velar next to a voiced dental. Since it didn't violate sound rules for consonant clusters within Latin words, it was quickly adopted.
5. Linguistics hasn't obviously embraced Occam's razor, like other sciences have with great success. Just because you don't have a "rule" for a disappearing C next to a D, doesn't mean the simplest solution doesn't carry. The alternative solutions put forth seem somewhat contrived and unconvincing, therefore the default "lay explanation" is good enough until linguistics experts come up with something a little more convincing. Since "HOC +DIE" is just a hypothesis, it shouldn't rile anybody up. It makes sense to me. Call it in "operating hypothesis" until some linguistics genius comes up with an alternative theory that makes as much sense.