# Day A single calendar day with 24 hours, the atomic unit of the temporal hierarchy of time periods (or time horizons). > [!info]- Canonical definition > This term is maintained in the [[vocab|PKM Vocabulary]] SKOS source, not here. > `pkmv:Day` · [term page](https://w3id.org/pkm/vocab/Day) · [Turtle](https://w3id.org/pkm/vocab/terms/Day.ttl) ## Scope Base temporal node in the Calendar subgraph: anchors PREV_DAY/NEXT_DAY ordering and all Day-prefixed note types in an Obsidian Ideaverse vault. ## Broader - [[Calendar (Term)|Calendar]] - [[Week (Term)|Week]] — partitive (ISO 25964) ## Related - [[Day Cluster (Term)|Day Cluster]] ## Collections - [[Day Collection (Collection)|Day Collection]] --- #vocab/term · created 2026-08-16 · modified 2026-08-27