血鬼術 (Blood Demon Art) is the series' name for every demon's supernatural ability, full stop — it's the coinage this whole dictionary is built around, and by Volume 5 it had already been established as strictly a demon's power, something the Demon Slayer Corps exists to fight, not to use. 爆血 is the technique that complicates that binary for the first time: Nezuko is a demon, but she's also the protagonist's sister, still fighting (in her own limited, sleep-cycled way) to protect humans rather than eat them. VIZ's translation makes no attempt to soften or distinguish her Blood Demon Art from a hostile demon's — it's labeled "BLOOD DEMON ART" exactly like Rui's or Enmu's, on the same page where Rui himself is casting 血鬼術・刻糸牢 (see the companion entry in this dictionary). The vocabulary doesn't discriminate between good and evil demons; only the story around it does.
Structurally, 爆血 is one of the plainest two-kanji names in the entire Blood Demon Art set — no classical reading, no borrowed navigation or martial-arts vocabulary, just "explode" plus "blood" stacked directly. That bluntness fits Nezuko's arc at this point in the story: she has no dojo, no decades of self-invented technique-naming the way Akaza does, and no spoken dialogue at all in most of Volume 5 (she communicates in muffled cries through her bamboo muzzle). Her one named ability arrives with the same directness as her muteness — a single hard consonant cluster, ばっけつ, that needs no elaboration to land.
The corpus captures the moment across two consecutive panels: "血鬼術" ("BLOOD DEMON ART") in one beat, then "爆血！！" ("EXPLODING BLOOD!!") in the next, mirroring the same style-then-name structure seen throughout this dictionary (羅針 preceded by 破壊殺, 刻糸牢 preceded by 血鬼術). The corpus's own JSON records the visible EN page as one page ahead of the Japanese original in this stretch of Volume 5 — the same offset that affects Rui's Cutting Thread Cage a few pages earlier — but the captured English text itself, "BLOOD DEMON ART" / "EXPLODING BLOOD!!", matches VIZ's actual print exactly once the correct page is checked.