You have it reversed.
The first use of may admits a counter-argument before introducing a main point. The second use expresses a possibility. On the one hand, Harry only delayed his return (not fully defeated him), on the other hand it's possible he'll never return to power.
Notice that in the 2nd definition, the word may is "used when admitting...". May by itself isn't enough to create this meaning, it's only used as part of the idiom. The While here is simply another part of the construction that admits one thing before introducing another.
While you may not believe me, I still stand by my story.
What is the meaning of the following line:
We ain't know what it meant
If you do a google search for 'we ain't know' you get quite a lot of returns for the phrase in a context in which didn't fits nicely.
These include:
1
We was young, we was dumb, we ain't know what was doing. But now that we older, older. Lets take these things slower, slower. Reset the button, button
2
And we ain't know just what he had in store. But now here we are ten years later, flows got greater. Bonds got closer, plus it's more haters
A lot of these uses of 'We ain't know' are in other rap songs. Rap has its own vocabulary.
In addition Wikipedia states:
some speakers of AAVE [African American Vernacular English] also use ain't instead of don't, doesn't, or didn't (e.g., I ain't know that).
Thus:
3
We ain't know it 'til General Wheeler come thru and tell us. After that, de massa and missus let all de slaves go 'cepting me; they kept me to work in de house and ...
That seems to clear the matter up, since didn't fits the context of the rap song "Yellow Brick Road" by (Eminem).
Here is the opening part of Verse 3 of the song:
My first year in 9th grade, can't forget that day at school
It was cool till your man MC Shan came through
And said that Puma's The Brand 'cause the clan makes troops
It was rumors but man, god damn, they flew
Must've been true because man we done banned they shoes
I had the new ones the Cool J, Ice land swayed too
And we just through them in the trash like they yesterday's news
Guess who came through next, X-clan debut
Professor X vanglorious exists in a state of red, black, and green
With a key sissies now with this being a new trend
We don't fit in crackers is out with Cactus albums
Blackness is in, African symbols and medallions
Represents black power and we ain't know what it meant
Me and my man Howard and Butter, we would go to the mall with 'em
All over our necks like we're showing 'em off not knowing at all
We was being laughed at you ain't even half black
You ain't supposed to have that homie let me grab that
And that Flavor Flave clock we gonna have to snatch that
Again, ain't fits perfectly as didn't.
The song is an auto-biographical narrative in which Eminem hearkens back to his first day(s) in 9th grade (a grade he failed twice before dropping out of high school) and remembering various events and moments. Not surprisingly an important topic is brands of athletic shoes, including Puma.
Eminem is a cracker, semi-offensive slang for a poor white boy. He attends a school with lots of black students. They make fun of Eminem when he and his friends wear African symbols and medallions. In the middle of this Eminem says we ain't know what it meant.
Ain't occurs 5 times in the song. All five instances are in Verse 3.
For those interested, here is youtube version that has the lyrics scroll as they are recited. There are a few mild-ish swear words. Stanza 3 begins right after the repeated chorus at 2:57.
Last, while I was pondering this question, I wrote the following section. It does not seem as relevant now, but I'm including it so that it wasn't a wasted effort. It also shows that you cannot always trust dictionaries. But then again, I've never been impressed with the ODO.
Ain't usually signifies
a negative form of to be
the negative form have not / has not
(Note: One of the ODO's examples for has / have not actually means aren't. This is the first example under 1.1 "More Example Sentences". In this example 'Baseball's origins ain't found till they're found', ain't means aren't. Not only is this clear from the clause itself; but the title is an allusion to the famous axiom of former New York Yankee catcher Yogi Berra: 'It ain't over till it's over.' In which ain't also signifies the verb to be. In English, axioms are stated in the present tense.)
Best Answer
Posted: A kind note to the community who chose to edit my spellings of the word nonstandard to non-standard... Nonstandard is the way I spell this word. More importantly, it is spelled this way in Collins, American Heritage, and the Unabridged M-W. The form non-standard is not found in any of these three American dictionaries. In other words: If it ain't broke, don't "fix" it!
The answer proper:
'Broken' is the past participle for 'to break'. It is being used as an adjective in
'Broke' is a nonstandard past participle for 'to break'. Reference. That is, it is considered to be nonstandard from the point of view of 'standard English'.
To avoid confusion, let's just call 'broke' colloquial for 'broken'.
Since ain't can also be considered colloquial, it makes perfect sense to find them together in the sentence
Thus, ain't does mean isn't here.
Example
As an example usage, in the "old days" of the cathode ray TV and before cable or satellite TV service, one had to adjust the rabbit ears antenna to get good reception on the TV (pronounced TV in this example).
Caution: nonstandard/regional language ahead:
Now suppose them rabbit ears broke? Well you're gonna use an aluminium fishing poll and duck tape to rig a new antenna. Now the TV works good again. Your wife don't like it, and she wants to buy new antennas. But since the television is working fine with the antenna you made, you say "Martha Mae, if it ain't broke, don't be trying to fix it. We can use the money on catfish bait."
However, one dictionary calls 'broke' an archaic past participle of 'to break'. If that is the case, then at one time it was not considered nonstandard. I have to check the OED for further details on this.