Every single opening

1. King's pawn opening, 2. Queen's pawn opening, 3. English opening, 4. Polish opening, 5. Ware opening, 6. Bird's opening, 7. Grob opening, 8. Kadas opening, 9. Anderseen opening, 10. Nimzowitsch-Larsen attack, 11. Saragossa opening, 12. Mieses opening, 13. Van 't Kruijs opening, 14. Barnes opening, 15. King's fianchetto opening, 16. Clemenz opening, 17. Reti opening, 18. Sodium attack, 19. Amar opening, 20. Van Geet opening.

I do not disagree with #2 but in a few cases have used different names. So... From left to right with Pawns (one square followed by two squares for each file), we have: 1. The Anderssen Opening 2. The Meadow Hay Opening; 3. The Nimzo-Larsen 4. The Orang-Utan aka Sokolsky; 5. The Saragossa 6. The English Opening; 7. The Mieses [but 1. d3 followed by 2. g3 can be the Venezolana] 8. The Queen's Pawn e.g. Queen's Gambit; 9. The Van t'Kruys 10. The King's Pawn e.g. Ruy Lopez; 11. The Barnes (or Walkerling) 12. Bird's Opening; 13. The King's Fianchetto 14. The Grob; 15. The Clemenz 16. The Desprez. And then with the Knights left-to right we have 17. The Potassium (or Durkin), 18. The Dunst, 19. The Reti, and 20. The Amar Opening or Paris Gambit. I really, really should get out more.

Both arguments, posts 2 and 3, are wrong.

Many don't have an opening name after one move, despite chess.com claiming such. They put in false names in nameless openings or variations, at move 1 and beyond!

1.a3 is indeed Andersson's Opening, but 1.Nf3 is not the Reti. 1.Nf3 has no name. It won't have a name until White and Black play moves to distinguish what is it.

1.Nf3 c5 2.c4 is the English Opening

1.Nf3 c5 2.e4 is the Sicilian Defense

1.Nf3 d5 2.c4 is now indeed the Reti Opening

1.Nf3 Nf6 2.g3 g6 3.Bg2 Bg7 4.O-O O-O 5.d4 with NO c4 is the Kingside Fianchetto. (With c4, it is something else, depending on Black - Fianchetto Kings Indian, Fianchetto Grunfeld, etc)

1.Nf3 Nf6 2.g3 d5 3.Bg2 (3.c4 is the Reti) c4 4.O-O Nc6 5.d3 is the Kings Indian Attack.

And it's not just transpositions. For it to be the Reti, White has to have played c4 and Nf3 without d4, and Black has to have played ...d5. 1.Nf3 Nf6 2.c4 g6 is not a Reti, it is an English. 1.c4 e6 2.Nf3 d5 3.g3 is not an English, it is a Reti. 1.c4 Nf6 2.g3 e6 3.Bg2 d5 is also a Reti, not an English.

Most openings are not determined by a single move.

@Thrillerfan that is a very good point indeed. I see that I for one have been somewhat facile. The position that 'some' first moves have an individual opening name whilst others only tend to be speciously associated with a particular name is accepted in this quarter. In my defence, the names for some of the lesser lines I cite have been around awhile: I checked them with 1980s books.