Ace's fruit sits at an odd angle in this dictionary: it's one of the series' most iconic powers, yet the reliable corpus range this dictionary draws from catches it almost entirely offstage. Ace debuts as a visiting older brother rather than a combatant in the scene this entry anchors on — he shows up at the Going Merry in Alabasta already having dealt with a Navy problem, and mentions his fire ability the way someone might mention having taken care of the dishes: この"メラメラ"の能力で, no exclamation points, no named attack. It's a deliberate contrast with how every other flagship fruit in this dictionary gets introduced — Luffy, Buggy, and Alvida all get a dedicated reveal panel with a proud declaration; Ace's power arrives as an aside inside a chat about family and Whitebeard.
That understatement is consistent with how VIZ handles the name everywhere else it surfaces in the corpus. A reader Question Corner at Vol. 20, p.66 asks Oda directly whether Ace's Flame-Flame Fruit "turns his body into flames" or "makes flames shoot out of his body," and Oda's answer splits the difference: technically option 1, but his signature Fire Fist move works like option 2 too, since it's really his whole Logia body reshaping around the strike. That's a rare case in this dictionary of the SBS column doing real explanatory work rather than just cataloguing the name — it's answering the exact ambiguity a first-time reader would have about what "becoming fire" means mechanically, something the main story never stops to explain directly in this corpus's covered range.
A later fan-favorites poll page (Vol. 40, p.120), ranking reader-voted techniques, casually drops the full formal name — "HE GOT HIS POWERS FROM THE FLAME-FLAME FRUIT... WHICH BURNS EVERYTHING IN SIGHT, IS INCREDIBLY POWERFUL!!" — confirming VIZ never wavers off "Flame-Flame" even in throwaway trivia captions. Between the three occurrences the corpus offers, the throughline is consistent: Ace's power is named plainly and named rarely, which fits a character introduced as already legendary rather than as someone discovering his own strength on the page.