tl;dr:
Certain kinds of words and phrases can in English function equally well as nouns as they can adverbs. Whether you prefer to call them nouns acting like adverbs or adverbs acting like nouns is a matter of religion only, since they are still doing the same job no matter what you call them.
The job they are doing is a deictic one, described at the end of this post.
“Now, now!”
Please do not be surprised that “dictionary.com” — or any other dictionary, for that matter — should have gotten this wrong. Grammar is not a dictionary’s strong point to begin with; it is a lexicon, not a grammar. But many dictionaries are still trapped in the fourth century when it comes to parts of speech, and modern syntactic analysis is not.
I would take especial care in crowd-sourced or unattributed “dictionaries”. This includes things like Wikipedia and Wiktionary, and it especially includes any reference as hip and now as Urban Dictionary.
Both nouns and adverbs can be drafted into doing the other one’s normal job. For example, when you say you did something last week, you are using the noun phrase last week adverbially. That doesn’t make week an adverb, though. Furthermore, this is as true in Spanish as it is in English: Lo hice la semana pasada does the very same thing. In both languages, it’s a simple adverbial phrase that happens to be noun phrase as well.
For your purposes, you want to see whether the noun–adverb swap can work the other way, too, particularly for the word now. And the answer is that it can.
To prove that now can act as a noun in English is most easily accomplished by showing it inflected into the plural or by using it as the subject of a verb, preferably as the head noun of a longer noun phrase with traditional prenominal adornments like determiners and adjectives prefacing it.
All these things are easily done.
Furthermore, to show that this is an age-old practice in English and not some flash-in-the-pan phenom pulled out of the Urban Dictionary’s backside, I shall begin in literature of the now-distant past.
In act 2 scene 2 of Timon of Athens, probably written around 1605, Shakespeare wrote:
O my good lord,
At many times I brought in my accounts,
Laid them before you; you would throw them off,
And say, you found them in mine honesty.
When, for some trifling present, you have bid me
Return so much, I have shook my head and wept;
Yea, ’gainst the authority of manners, pray’d you
To hold your hand more close: I did endure
Not seldom, nor no slight cheques, when I have
Prompted you in the ebb of your estate
And your great flow of debts. My loved lord,
Though you hear now, too late—yet now’s a time—
The greatest of your having lacks a half
To pay your present debts.
That has now serving as the subject of be, or so it appears. Some might try to argue that use in a copula may not be good enough evidence, and for those, not even this more famous citation from the start of Richard III (probably written around 1592) suffices:
Now is the winter of our discontent
Made glorious summer by this sun of York;
And all the clouds that lour’d upon our house
In the deep bosom of the ocean buried.
I think those are enough, but some disagree, claiming that it is fine to have adverbs to either side of a copula:
- Soon is immediately.
- Often is always.
- Quickly is carefully.
I disagree. After all, winter is obviously no adverb in Now is the winter, and neither is now. But I do not wish to argue this with them, having yet stronger evidence to present.
Skipping forward a century, in 1711’s The Works of the Right Reverend, Learned and Pious, Thomas Ken: Preparatives for Death we find these half-dozen examples:
On the short Nows God sends,
My everlasting state depends;
And should I but this Now
To cultivate my soul allow,
Short as it is, ’twould me prepare
To be of bliss eternal heir.
I oft made solemn vows
To consecrate to God my Nows;
This Now, I would begin,
But worldly thoughts keep rushing in;
Then I the next, and next designed,
When the next came, I change my mine.
I by experience found
The more I to the world gave ground,
The less my soul would heed
The Nows God for my good decreed;
When sin was up to habit wrought,
Of Now I seldom had a thought.
All but the sixth are clearly nouns: they have determiners in front of them like this, the, and my; and they are thrice inflected into the plural nows. Only nouns can do those things, and so that these must here be nouns no question can remain.
Jumping ahead one more century to 1820, Sir Walter Scott wrote in The Monastery:
“There are actions, father,” returned Edward, “which brook no delay, and this is one. It must be done this very now; or it may never be done.”
The OED considers that a substantive (that is, noun) use of now.
As a constituent, this very now is clearly acting adverbially to describe when something must be done. But when you look inside that constituent, you clearly find a noun phrase. We do not use this on anything but a noun, and very is there an adjective, not an adverb. We do not apply adjectives to adverbs, but to substantives. Therefore this now can be nothing other than a noun.
If you removed the two front words from the adverbial noun phrase this very now in the Scott citation and produced therefore this compressed version:
“There are actions, father,” returned Edward, “which brook no delay, and this is one. It must be done this very now; or it may never be done.”
If now must be a noun in this very now, even when used adverbially, mustn’t now also be noun when stripped of the pieces we used to prove it a noun, the this and the very?
The sticky bit
We now come to the primary sticking point for most people: they don’t think that when now is used as a prepositional complement it has to be an noun. They think it might still be an adverb. Returning to the Ken citation given above, the final example is one of those places where some will argue that now has to be an adverb.
That sixth example is Of Now I seldom had a thought, or in more conventional ordering, I seldom had a thought of Now. I maintain that this must also be a noun, even if for no other reason that the previous five examples given immediately before it are so clearly nouns, that then so too must it also be a noun.
Those who dispute this position believe that that a prepositional phrase need not inevitably supply a nominal complement to the preposition.
- until now
- until today
- until yesterday
- until midsummer eve
- until I’m good and ready
- until the cows come home
- until finished
I am discontent with calling any of those complements “adverbs”. The clause examples are larger constituents, but do please that the last example of finished does not actually have a past participle serving as the prepositional complement. This is actually a reduced clause for something like until it is finished or until you are finished, with the obvious elision of something that in any larger context would be so obvious as to allow for its omission.
I really believe that all those prepositional objects are acting as nouns, one way or the other. I do not believe we can just stick any old adverb in there and have things work. These are all ungrammatical:
- until besides
- until instantly
- until soonest
- until out in back
Nonetheless, some adverbs clearly do work fine there:
- until recently
- until lately
At which point one might reasonably ask how there can be any difference between until now and until recently.
The answer, I believe, is that there is not one. But that does not mean those are adverbs there. I think it is better to analyse those not as adverbs but as adverbs acting as nouns.
I’m afraid that the eight sacred parts of speech enumerated by Donatius back in the fourth century are not sufficient for modern syntactic analysis. However, many dictionaries refuse to step away from them, and that is why you find such things in them. They do not admit the notion that what is sometimes an adverb may at other times be a noun.
Thus spake Oxford
The OED, however, is not one of those. It points out many places that now can be a noun (or a substantive — un sustantivo, como quieras). My citations given above were all originally from the OED’s noun examples, although I gave them a fuller treatment than it did.
The OED attests now used as an adverb, as a conjunction, as a noun, and as an adjective.1 The adverbial and conjunctive uses are in sections I an II of that entry, the substantive uses in section III, and the attributive and adjectival uses are in section IV.
1. All four of which have I used at least once is this posting. :)
Interestingly, the uses with a preposition are not in section I; they are in section III with the other noun uses. I therefore present section III for your contemplation:
III. 13. a. With preps., as by, ere, for, or, till, unto, now.
- C. 825 Vesp. Psalter lxx. 17 ― Oð nu ic forðsecʒu wundur ðin.
- C. 1200 Ormin 14066 ― And tu þe gode win till nu Aȝȝ hafesst hidd and haldenn.
- A. 1300 Cursor M. 12800 ― Es þou helias halden til nu, Crist or prophet, quam to bu?
- C. 1450 Cursor M. 17785 (Laud), ― Ye wold nevir yt leve or now.
- C. 1450 tr. De Imitatione i. xxiv. 35 ― If þou haddist lyued unto now in worshipes & lustes of þe worlde.
- C. 1500 Melusine 121 ― But as for now I shall reste of hym and I shal retourne there.
- 1592 Shaks. Ven. & Ad. 1062 ― Her eyes are mad that they have wept till now.
- 1619 Fletcher Mons. Thomas i. iii, ― No word of visitation, as ye love me, And for now Ile leave ye.
- 1860 Thirlwall Rem. (1877) I. 395 ― Without this, she would have fallen ere now under the blows.
- 1885–94 R. Bridges Eros. & Psyche Feb. iv, ― She is not hence by now six miles at most.
b. from now (forth, forthward, forward).
- A. 1300 Cursor M. 3758 ― In dew and gress sere o þorth Sal be þi blissing fra no forth.
- A. 1300 Cursor M. 10976 ― Þou sal be dumb fra nu, Til þat he be born.
- C. 1400 Hampole’s Wks. I. 221 ― And þou sall lufe gastely ilk a mane, and flee fra now forthwarde to lufe fleschly.
- 1503 Surtees Misc. (1890) 30 ― John Mitteley & his heires frome now forthe shall wall up··the utter west syde of his swynstye.
- 1855 Kingsley Westw. Ho! xvi, ― I could live very well from now till Doomsday without [etc.].
- 1890 Spectator 10 May 651/2 ― The Gladstonians could talk with ease on one line of one clause from now till Christmas.
14. a. As sb. The present time. Also Comb.
Gower uses time now in the same sense.
- 1390 Gower Conf. I. 32 ― To peise now with that beforn, The chaf is take for the corn.
- 1390 Gower Conf. III. 346 ― Ensamples thou hast many on Of now and ek of time gon.
- 1549 Strype Eccl. Mem. 431 ― The tyme is tourned: then was then and now is now.
- 1607 Shaks. Timon ii. ii. 152 ― Though you heare now (too late), yet nowes a time.
- 1631 Celestina vii. 97 ― Now is now, and then is then; when time serves, we will follow your counsell.
- 1655 Fuller Serm. 29 ― Now is an atome, it will puzzle the skill of an angell to divide.
- 1854 Patmore Angel in Ho. i. ii. x, ― Where Now and Then are no more twain.
- 1861 Angus Serm. 43 ― Base and profligate now-wasters.
- 1861 Angus Serm. 44 ― It is only a make-believe of happiness which does not dwell in now.
b. So with the or this.
- 1633 Ford Broken Hrt. iv. i, ― Now, uncle, now; this Now is now too late.
- 1685 Dryden Threnodia 28 ― With scarce a breathing space betwixt, This now becalmed, and perishing the next.
- 1713 Rowe Jane Shore iii, ― This present now Some matters of the State detain our leisure.
- 1771 Wesley Wks. (1872) V. 392 ― Enjoy the very, very now, by enjoying Him ‘whose years fail not’.
- 1820 Scott Monast. xxxii, ― It must be done this very now; or it may never be done.
- 1851 Brimley Ess. 183 ― Plant the great hereafter in the now.
15. a. A present point or moment of time.
- 1630 Drumm. of Hawth. Flowers of Sion Poems (1856) 179 ― Still is the same thy Day and Yesterday An undivided Now.
- 1692 Dryden Eleonora 306 ― We can scarcely say she died; For but a now did heaven and earth divide.
- 1751 Harris Hermes Wks. (1841) 146 ― If a point or now were extended, each of them would contain within itself infinite··other nows.
- 1801 Southey Thalaba i. xxviii, ― Time is not here, nor days, nor months, nor years, An everlasting now of solitude!
- 1870 Emerson Soc. & Solit. Wks. (Bohn) III. 71 ― An everlasting Now reigns in nature.
b. With possessive pronouns.
- A. 1668 Sir W. Waller Div. Medit. (1839) 146 ― In this my day, or rather in this my now.
- A. 1711 Ken Preparatives Poet. Wks. 1721 IV. 7, ― I oft made solemn vows To consecrate to God my Nows.
- C. 1859 Lowell Ode to Happiness 49 ― Man ever with his Now at strife.
I am unconvinced that the OED believes that the uses with prepositions count as adverbs; after all, why then did it group sense 13 with the substantive uses of senses 14 and 15? But in any event, now is quite clearly able to function as a noun, as primary sense 14 and 15 prove.
¿Y en castellano?
Now that that’s out of the way, I must note that even El Diccionario de la Real Academia Española hedges its bets on ahora, calling it in places a “locative adverb” rather than merely an adverb. It includes this example:
Por ahora, su salude se resiste.
There it means for now, as in “For now, his health is holding.” There it specifically calls ahora not an adverb but a locative adverb — whatever that means. Apparently it is something that can function as the object of a preposition.
The RAE does actually provide the example of Hasta ahora, but there it just calls the whole thing an expresión usada — a set phrase, and does not attempt further deconstruction.
Spanish is considerably less flexible about parts of speech than is English. You must work rather hard to find instances of plural inflections of words like ahora or ayer — although these can be found if you look hard enough:
So sometimes these words do get nouned even in Spanish, or else you couldn’t find them in the plural. (I’ve left out algunas mañanas, since that can mean some mornings not just some tomorrows. I’ve also left out algunos hoyes for some todays because I believe all examples I found on the internet to be catachrestic for algunos días, which as a phrase is wholly unremarkable.)
The imputed gender for ahora is clearly derived from la hora, but as you see, people aren’t sure what gender to assign ayer when they convert it into noun, since nouns ending in ‑r can come in either flavor. So both algunos and algunas can be found prefixing the now-plural noun ayeres in the wild. Barely.
Fortunately for English, we have no possibility of such confusion of gender with all our yesterdays — nor with our tomorrows for that matter, as Lady Macbeth famously proves when she uses each not just as nouns but indeed even as subjects of verbs:
To-morrow, and to-morrow, and to-morrow,
Creeps in this petty pace from day to day,
To the last syllable of recorded time;
And all our yesterdays have lighted fools
The way to dusty death. Out, out, brief candle!
Life's but a walking shadow, a poor player,
That struts and frets his hour upon the stage,
And then is heard no more. It is a tale
Told by an idiot, full of sound and fury,
Signifying nothing.
On Deixis
Words like here, home, and now — words that seem to be both nouns and adverbs — really are in a special category of their very own. They quite comfortably serve multiple possible “duties” in English sentences, sometimes acting more like a noun, at other times acting more like an adverb, and frequently acting like both.
If you want to further research the literature for this particular sort of dual-lived words and phrases and what they are doing, you should know that they are called deictics, and what they’re doing is called deixis.
Amongst other things, deictics can include both locative (place) and temporal (time) deictics. Locative deictics are “place-words” that answer where-questions and include here, there, and yonder. Temporal deictics are “place-words” that answer when-questions, such as today, tomorrow, yesterday, and now, as well as longer phrases like last year and the week after next.
Best Answer
Your initial discomfort with
likely stems from only after usually meaning "not until."
This makes sense because only modifies the entire prepositional phrase, not merely the time expression.
Here, I'm commenting on the relative brevity of the three days compared to the two weeks, which more accurately reflects the situation in your example sentence:
It has been said that the skill in playing a musical instrument is the only thing that degenerates more quickly without practice than active skills in a second language. If you are regularly using those skills, then you will not lose them.