The title refers to the three Dragon Slayers present in the battle: Natsu (Fire), Gajeel (Iron), and Laxus (Lightning).
You can find this episode on various streaming platforms, including: Apple TV Crunchyroll Fairy Tail Episode 47 - Anime Evo Fairy Tail Episode 47
Fairy Tail , titled " Triple Dragons ," is a climactic turning point in the "Battle of Fairy Tail" arc. It is best known for the high-stakes showdown between Laxus Dreyar and the combined forces of Natsu Dragneel and Gajeel Redfox . Key Plot Summary The title refers to the three Dragon Slayers