Sure you can maybe rationalize it a bit and translate it as blade because Whitebeard's weapon isn't a sword, but if anything that would just prove that Oda is nowhere near as pedantic and simply considers any weapons he wishes as being potential Meito, and to add to that, I would hardly consider a lance to be a bladed weapon, it has a sharp point, if you consider that a bladed weapon you may as well consider Kaido's club as one given it has pointed spikes on it lmfao.
It has a blade in it no? Mainly because Oda considers a Trident like Mogura as a Meito too, which is why Spear being there makes sense too.
Let's be real, the spikes on Kaidou's club have been nothing but aesthetics tbh. It's treated as blunt damage by Oda and Kaidou clearly isn't smashing skulls in with it.
Also, if we're saying the real life Wazamono are a 1-1 to One Piece's Meito, well, the real life Wazamono are entirely and specifically comprised of swords, no polearms, daggers, tridents or whatever at all, so again, it shows that Oda simply doesn't care to be so hyper specific and simply does whatever he wants to.
Probably you do have a point.
You glossed over the Yamato bit, it's not so much her being included in the page, it's the fact her club is listed in the unknown category instead of the ungraded category, it greatly implies that her club has a grade as well as acknowledging the fact that clubs aren't impossible to have a grade, otherwise they'd automatically be placed in the ungraded section.
I agree that everything changes if Yamato's weapon gets a grade. But as far as we know, it can still be ungraded, no?
The list of "Unknown Grades" also contain weapons like Hawkins Straw Sword, Brook's Soul Solid, Franky's Franken sword & Big Mom's Napoleon.
It had even more entries, which are quite frankly absurd like - T Bone's broken sword, Bastille's sword which was shattered, Kuro's claws, Don Krieg's Spear (a Spear entry), heck even Johnny & Yosaku's swords.
Ofcourse these aren't Meito's, so i guess the Yamato argument falls apart too.
Also acting like it's mere databook material is downplaying it a bit, it's so official even that it literally replaced the weekly release of the manga for an entire month after 1053, that goes quite a bit beyond just another databook.
I'm not dis-crediting the source, it's 100% canon.
But just because some weapons were mentioned in the page along with Meito's doesn't mean they are Meito's.
Enma is never confirmed to be a cursed blade, in fact Sukiyaki clearly highlights a distinction between them.
If I remember correctly, he says something of the likes that "Enma too works very much like a Cursed Blade" & not this.
Enma is never confirmed to be a cursed blade
Again, Enma is never confirmed to be a cursed blade
From it's own maker:
And he considers Enma to be his best ever work, a Sword that has a very high requirement for it's wielder.
Does the sword have a serious disposition/temperament? Yes.
Do people fear wielding the sword? Yes.
Did the sword test/choose it's wielder? Yes.
Were people able to tame it? Yes.
It is no coincidence that Cursed Blades lore were explained when Zoro was in the process of taming Enma, 1033 for Enma was what the Loguetown scene was for Sandai Kitetsu.
The Shodai is regarded as being superior to Enma in rank and quality, not requirement.
A superior ranked Cursed Blade will have an even superior requirement to fulfill, that's just simple logic.
Enma had a harder requirement than Sandai for example.
Enma is the only blade in the manga to have any form of power test
Refer the Kozaburo exposition about Swords, their Dispositions & what it means to be a Swordsman.