Difference between double attack and fork???

I think that while a fork attacks two or more pieces simultaneously (as in Knight fork), a double attack involves 2 pieces attacking the same piece (like a Rook and a Bishop attacking the King simultaneously).

In my opinion, a fork is a proper subset of a double attack which covers a greater category of attacks.

If I were to put this in my words, a fork occurs when one piece attacks two opposing pieces simultaneously without itself being attacked while a double attack occurs when one or two pieces attack two opposing pieces simultaneously on the same move and none of the two opposing pieces was attacked on the previous move.

A fork involves only one piece attacking two pieces simultaneously, usually a knight or a bishop; while a double attack is an improper term except for double check (implication is that king has to move as there is no block or take of attacking piece in double check), which is probably what you meant. Some do say or use "double attack" but it occurs often usually over a series of moves so has little meaning. Skewers and pins are also "tactics" used often and you should learn about them too.

I think a double attack is when a piece has two threats (pawn+Piece, Piece+check etc...)

Fork is when one piece threatens two pieces (Knight, bishop, rook, queen, king)

A fork occurs when a single piece attacks two pieces. A double attack is when a piece moves to attack a piece, revealing a discovered attack on another piece.

I don't think that's correct

Well, that is the only reason I can come up with because otherwise they are the same thing.

No read my post

fork

double attack

So, it is a double attack if multiple pieces are involved but a fork when a single piece is attacking two pieces?

no

No, it's a double attack if a piece is attacking multiple things at the same time

A fork is only if a piece is attacking multiple pieces at the same time

Look at my example #2, white plays Qb3 attacking the b7 pawn, and at the same time putting pressure on the f7 square.

In example #1 it's a fork as the knight is attacking two pieces at once

Can anyone provide an example of a piece attacked three times more  in a move?

So this is a double attack right? The queen attacks both the f7 pawn, threathening checkmate; and the unguarded e5 pawn.

yes

But this is a fork because the queen is attacking the king and the rook at once?

yes

So in both examples:

• One piece is attacking more than one piece/pawn with a single move.
• The attacking piece cannot be captured.
• The attacked pieces/pawns are not defended.

I still can't quite understand the difference...