An ability that appears in larger models without being present, or predictable, in smaller ones.
The definition itself is disputed: what this term refers to depends on who is using it. Read any argument that leans on it twice.
The claim: as models scale, some abilities, multi-step arithmetic, certain kinds of reasoning, seem to appear abruptly at a size threshold rather than improving smoothly, making the next scale-up's capabilities hard to predict.
The dispute is about whether that abruptness is real. Influential work argues many "emergent" jumps are artifacts of all-or-nothing metrics: the underlying competence improves smoothly, but the score snaps from zero to passing. The definition itself is contested, and the stakes are large either way, if emergence is real and unpredictable, both capability forecasts and safety arguments inherit that unpredictability.