The slice of a page's content an AI system actually uses to support a sentence, drawn from a fixed per-query word budget.
A grounding chunk is the slice of your page's content that an AI system actually selects to support a sentence in its answer — not your full page, just the part it uses. In Google's grounding, only these chunks genuinely back the answer, which is why Google tends to cite everything it shows.
Our analysis of 7,060 queries and 2,275 tokenized pages found each query works from a fixed grounding budget of roughly 2,000 words, split across sources by relevance rank. The #1 source gets around 531 words (about 28% of the pie); #5 gets around 266. The typical page contributes about 377 words, and coverage drops sharply as pages get longer — a tight 800-word page can get over 50% coverage while a 4,000-word page gets about 13%.
The lesson for content strategy is that density beats length: you compete for share of a fixed budget, not by adding words. Grounding chunks are the raw material behind the grounding snippet and the wider web search grounding process, and your rank determines your share.
