Can one explain, why Sicilian is a "defence"? I mean 1...e5 is not a defence, merely a goup of openings - Italian game, Spanish game, Russian game, Vienna game etc. depending on next couple of moves.
Sicilian seems to be as much variation heavy, yet these are all variations of a defence rather then seperate openings.
Attacks refer to lines specifically defined by a line that ends with a move of White's. So do "Openings" (like the Catalan Opening) or Games (like the Scotch Game)
A Defense is a line defined where the ultimate move that defines the opening is determined by a move by Black.
Examples:
The Kings Indian Defense, Four Pawns Attack
1.d4 (Not defined yet) Nf6 (still not defined) 2.c4 (still undefined) g6 (still undefined) 3.Nc3 (still undefined) Bg7 (BAM! We now have the Kings Indian "Defense" while 3...d5 would be the Grunfeld "Defense") 4.e4 d6 5.f4 (BAM! This is the Four Pawns "Attack" defined after 5.f4)
Others:
1.e4 e5 2.Nf3 d6 (Philidor's DEFENSE)
1.e4 e5 2.Nf3 Nf6 (Russian DEFENSE or Petrov's DEFENSE)
1.e4 e5 2.Nf3 Nc6 3.Bb5 (Spanish OPENING)
1.e4 e5 2.Nf3 Nc6 3.Bc4 (Italian GAME) 3...Nf6 (Two Knights DEFENSE).
1.e4 c5 (Sicilian DEFENSE) 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 g6 6.Be3 Bg7 7.f3 (Yugoslav ATTACK)
I hope you get the point by now.
I do not see any of the following mentioned yet:
Kalashnikov (not the same as the Lowenthal, which is 5...a6 - Kalashnikov is 5...d6)
Four Knights Sicilian (1.e4 c5 2.Nf3 e6 3.d4 cxd4 4.Nxc4 Nf6 5.Nc3 Nc6)
Levenfish Attack (6.f4 against the Dragon)
Hyper-accelerated Dragon (2...g6)
Nimzowitsch Variation (2...Nf6)