What term is used to describe the winning player?

Just trade "side" for "player," this implies the position rather than the skill level. In specific positions you could refer to "White" and "Black."

Just trade "side" for "player," this implies the position rather than the skill level. In specific positions you could refer to "White" and "Black."
Good observation. I neglected to mention another problem, though: the word "side" is ambiguous, and could refer to a side of the board. So you're suggesting "superior side"/"inferior side" and "winning side"/"losing side"? That does sound better, I think. Thanks. I'll have to think about that. It's odd that I don't recall any chess book using such terms, but then most chess books are also hung up on algebraic notation, therefore are hung up on specifically White vs Black, which is a level of detail what I want to avoid.

Chess books normally say things like "white is better"/ "black is better" - it's pretty much taken as a given that refers to the position and not the person playing. You could say White stands better if you want to be really unambigious but that's not necessary. Finally, += / =+ denote the exact same thing and are often used in order to conserve space etc.

You don't describe the person, but the position. Like white has a winning position, or black's position is better etc.

Chess books normally say things like "white is better"/ "black is better" - it's pretty much taken as a given that refers to the position and not the person playing. You could say White stands better if you want to be really unambigious but that's not necessary. Finally, += / =+ denote the exact same thing and are often used in order to conserve space etc.
Here's a specific example of what I'm trying to do... Suppose you're trying to describe in general how to do the basic mate with two bishops without using any diagrams. You can't say "White moves his bishops side by side..." because it could be Black who has the bishops. What is a concise way of saying that in general, without having to say something verbose like "The side with the two bishops puts his bishops side-by-side"?

it's an interesting question. i've never really thought about it. but possibly 'opponent','opposition','opposing player' if avoiding colour. otherwise simply colour.

but as for the winning player and a superior term, hmmm. it seems like there should be one. I just can't think of it.

By the way, here's one reason that question came up: I was creating the headers on my little table of basic endings...
https://www.chess.com/forum/view/endgames/help-sqod-finish-his-basic-ending-table
...and no term I chose worked very well. I can see this terminology problem is going to extend to other written descriptions, as well.

You don't attribute superior position to the player, but rather his/her colour of piece. "White has dominance" or "The position favours black."

Silman, along with the majority of authors, state that White has the winning material and describe the moves with white/black. Some state that you have the winning position and describe the moves with you/he. Some refer to the attacker and the defender.
I prefer the middle choice because:
1. It doesn't imply an inate advantage to a color.
2. Using "you" gets the audience more involved.

Player in Winning Position = Advantaged
Player in Losing Position = Disadvantaged
Works well I believe, supports the fact that either player could still win which is always true.
Also += / =+ is infallible.

Saw someone mention that it is bad etiquette to ask for a draw if the weaker side at the time you ask for the draw.
Is this true even if slightly behind (ahead positionally down a pawn or vice versa for instance, since one might be better than the other in a given game)?
I have asked for a draw when I felt my side was the weaker side and it has been accepted before but I had no idea it was bad etiquette.
I am not a very good player and a noob I guess when it comes to etiquette. I certainly do not want to be rude to an opponent.
Does there exist a term to describe the player with the theoretically superior position--superior either in material force or position--in a given game, and if so, what is that term? I've been using the terms "superior player" and "inferior player," but those sound like they describe a player's *skill* rather than the position, so that is confusing terminology. Maybe "winning player" and "losing player"? But that sounds like the situation could change, rather than being theoretical in nature.