Some openings are named after the players who spent their whole career playing a particular type of opening. For eg. Alekhine for Alekhine Defense, Philidor for Philidor Defense, William Evans for Evans Gambit. While some are named after the places they were played like French Defense, Dutch Defense, etc. So, my question is, who decides that a particular opening will be called a certain name? Is it FIDE, World Chess, or another organization?
who decides that a particular opening will be called such and such?
The simple answer is "Chess players".
Wittgenstein's principle of "The meaning is the use" also applies to chess. If more chess players over time call a particular opening "A" rather than "B" then it becomes "A".
Is it FIDE?
No. FIDE actually tried back in the early 1930's but failed miserably. Their one success was in changing the Greco Counter Gambit to the Latvian Gambit. Chess historian, Edward Winter, wrote about this here.
The delegates from Czechoslovakia agreed to draw up a draft by 1 April 1930. At that year’s FIDE Congress, in Hamburg, a committee was set up (involving the federations of Czechoslovakia, Germany, Holland, Poland and Sweden) to prepare by the following year a report on the draft (source: FIDE minutes of the 1930 Congress, page 18). In the summer of 1931 FIDE met in Prague and, as noted on page 7 of the minutes, the Secretary of the Czechoslovakian Federation, Josef Louma, reported that the draft had been revised by a large number of chess figures, including Tartakower and Grünfeld. Another year went by. Page 9 of the minutes of the Paris, 1932 Congress contained a brief note by the FIDE President, Alexander Rueb, that no further news was available on the openings project (which was described as ‘important mais difficile et considérable’. But then at Folkestone in 1933 the delegate from Czechoslovakia, Jan Bedrníček, presented a document by Louma, still described as a draft (‘avant-projet’). Rueb extended his warm congratulations, and the minutes (page 4) also reported that the work would be published, at FIDE’s expense, with profits going into the FIDE coffers. A further year passed, and it was not until the Zurich Congress in 1934 that, as noted on page 5 of the minutes, FIDE was able to announce with great pleasure that the book had just appeared
Winter goes on to give some examples of their chosen names:
- 1 b4: ‘Partie Hunter-Englisch’
- 1 d4 d5 2 Nd2: ‘Partie Breyer’
- 1 d4 Nf6 2 c4 g6 3 ~ Bg7: ‘Défense Dr Euwe de la Partie indienne’
- 1 e4 c5 2 Nf3 Nf6: ‘Défense Kljatzkine de la Partie sicilienne’
- 1 e4 e6 2 d4 d5 2 Nc3 Bb4: ‘Défense Maroczy-Nimzowitch de la Partie française’
- 1 e4 e5 2 Bc4: ‘Partie Spielmann’
- 1 e4 f5: ‘Gambit en second’
- 1 Nf3 d5 2 e4: ‘Gambit de Léopol’.
In those days French was the official language of FIDE although I don't think that was the reason they failed so utterly.
You could argue the openings listed in the Encyclopedia of Chess Openings (ECO), however they were chosen by the editors, are the standard reference for opening names, which seem to be pretty widely adopted in opening explorers (lichess, chess.com, see What are the letters and numbers next to an opening's name on online services?) and chess publications (chess programming wiki claims it is a de facto standard: https://www.chessprogramming.org/ECO).