How do you define isolated pawn, passed pawn.

How do you define isolated pawn, passed pawn? What is the difference between them?

An unpopular pawn. Picked on, passed over, and isolated from social activities.

Strangely, I don't recall ever reading anything written by you tyrst that wasn't a joke.

An isolated pawn is one that has no friendly pawns on an adjacent file, which is bad because that means that your pieces have to defend it. A passed pawn is a pawn with no enemy pawns in front of it on the same file or on adjacent files, which is good because that means it can march onto promotion and your opponent's pieces need to defend against it.

I hope this helps.

I think the confusion is that a pawn can be both isolated and passed -- like I show below white's pawn starts out only isolated and then becomes a passer.

Thanks tryst, for the defn from the social point of view.

@oinquarki: Thats a good, accurate defn. Thnx.

The confusion arises when a pawn is both isolated and passed. for eg: I tend to call white f3 and h4 pawns as isolated, because of the negativity associated with them as they do not support each other. But for c6,b5 I refer them passed pawns.

Whereas in reality, all four of them are passed, and f and h are isolated too.

And being isolated isn't all negative -- famously, many openings lead to isolated queen's pawn positions (say, 1.d4 d5 2.c4 dxc4 3.e3 e5 4.Bxc4 exd4 5.exd4), and the fact that White has two (half-)open files next to the pawn is quite useful.