It shows up every now and then, a distinction between ‘hold’ versus ‘use’/‘wield’.
For example, in Xanathars Guide, the Kensei Monk Agile Parry gets +2 AC if ‘holding’ a weapon, as opposed to ‘wielding’ it to attack.
In the case of the Fighter Fighting Style, Dueling, the natural weapon isnt being ‘wielded’ to attack, so the one-weapon attack gains the +2 damage bonus.
I agree that the books use different terms and that they have different meanings. Indeed, if you read
my post being responded to, you'll see that my argument relied on that fact. TheCosmicKid said that you can't use inference or fuzzy logic like that when evaluating a rule.
My point is: If you're not supposed to infer things or use fuzzy logic, then what is the game definition of
wield? Because, as you may have guessed, there isn't one. If we need to rely on the strict wording of abilities like fighting styles, how do the rules tell us we're meeting the requirements? There's no rule that says "If you do X you're wielding, if you do Y you're holding." Indeed, the only game way to tell that you're wielding a weapon is if you took an action that required you to be wielding one! Whether or not you are or are not wielding a weapon is 100% based on the collective agreement of the table
and nothing else.
So, if wielding a weapon is not strictly defined, then why should we think that it isn't reasonable to judge rules by comparing the perceived ideal case with the case that your player is attempting? If we're already asked to make a judgement call just to use the fighting style in the first place, why does it seem so unreasonable to make a call that an unarmed strike doesn't count for purposes of the fighting style?
Think of it this way. The argument was that unarmed strike cannot be a weapon because things like duelist say you can't do it while wielding a second weapon. What about a metal gauntlet? No character in full plate can use duelist? Okay, say we adopt a rule that a metal gauntlet just increases damage from unarmed strikes. If a metal gauntlet also isn't an unarmed strike, what about a cestus? How about just spiked gloves? What about a Battlerager's spiked armor? What about a spiked shield? What about a normal shield? What if I've got Polearm Master and I'm using a spear (errata) or a quaterstaff in one hand? Does the bonus attack get the duelist bonus?
How about if you're a 12th level Fighter holding a spear. You attack once (duelist bonus), attack again and throw the spear (no bonus), and then draw a dagger and attack again. Do you get the duelist bonus with
that dagger?
The only way it makes sense is if you say, "The point of the duelist fighting style is that you're representing a particular style or form of melee combat. If you're using just one-handed combat forms and attacking with a weapon intended for one-handed combat forms, you meet the requirements. Nothing else really matters. As long as the forms your character is using are the forms of a one-handed duelist and they're doing them with a weapon meant to be used in one hand, you get the bonus."
In other words, it boils down to what your character is actually doing and not at all what the rules say.