{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.day","code":"thing-q573","url":"https://ver.cy/models/thing/q573/","name":"day","alternateNames":[],"kind":"thing","status":"published","version":"0.2.0-wave.1","language":"en","classifiers":{"family":"Thing Registry","category":"Cross-cutting context","entryKind":"thing","plane":"XCT","domain":["XCT.TME"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"A unit of time of 86,400 seconds, and the period of one rotation of the Earth relative to the Sun, reckoned from midnight to midnight in civil use.","purpose":"Let an agent distinguish the day as a unit of time, as a solar period and as a calendar date, and handle time zones and daylight saving correctly.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["A unit of time and a solar cycle, which differ slightly","The civil day follows a time zone and can be 23 or 25 hours on daylight saving changes","Distinct from daytime, the light part of the day","A calendar date names a particular day"],"structure":{"bundles":[{"id":"unit-and-astronomy","name":"Unit and astronomy","description":"The day as unit and as rotation.","layers":[{"id":"unit","name":"Unit","description":"Definition in seconds.","findings":[{"id":"unit-finding","name":"Unit definition","description":"The unit and its relation to SI.","questions":[{"text":"Which definition of day applies here?","kind":"definition"},{"text":"Does the precision required make the difference matter?","kind":"boundary"}]}]},{"id":"astronomy","name":"Astronomical day","description":"Solar and sidereal days.","findings":[{"id":"astronomy-finding","name":"Astronomical basis","description":"The astronomical day used.","questions":[{"text":"Is the solar or the sidereal day meant?","kind":"definition"},{"text":"How does day length vary over the year?","kind":"measurement"}]}]}]},{"id":"civil-day","name":"Civil day","description":"Days in time zones.","layers":[{"id":"zone","name":"Time zone","description":"The zone the day belongs to.","findings":[{"id":"zone-finding","name":"Zone rules","description":"The zone and its offset rules.","questions":[{"text":"In which time zone is this day reckoned?","kind":"definition"},{"text":"Does a daylight saving change fall on it?","kind":"boundary"}]}]},{"id":"boundaries","name":"Day boundaries","description":"Midnight and edge cases.","findings":[{"id":"boundaries-finding","name":"Boundary rules","description":"When the day begins and ends.","questions":[{"text":"When does this day begin and end?","kind":"definition"},{"text":"How are events near midnight assigned?","kind":"action"}]}]}]},{"id":"counting","name":"Counting days","description":"Durations and deadlines.","layers":[{"id":"durations","name":"Durations","description":"Calendar and business days.","findings":[{"id":"durations-finding","name":"Counting rule","description":"Which days are counted.","questions":[{"text":"Are calendar days or business days counted?","kind":"definition"},{"text":"Which holidays are excluded, and in which jurisdiction?","kind":"boundary"}]}]},{"id":"deadlines","name":"Deadlines","description":"Day-based deadlines.","findings":[{"id":"deadlines-finding","name":"Deadline rule","description":"How a day-count deadline is computed.","questions":[{"text":"How is this deadline computed in days?","kind":"definition"},{"text":"What happens when it falls on a non-working day?","kind":"boundary"}]}]}]},{"id":"naming","name":"Naming","description":"Weekdays and dates.","layers":[{"id":"weekday","name":"Weekday","description":"The day of the week.","findings":[{"id":"weekday-finding","name":"Weekday naming","description":"The weekday and numbering convention.","questions":[{"text":"Which weekday is this, and which numbering convention applies?","kind":"definition"},{"text":"Does the week start on Monday or Sunday here?","kind":"boundary"}]}]},{"id":"date","name":"Date","description":"The calendar date.","findings":[{"id":"date-finding","name":"Date identifier","description":"The date naming this day.","questions":[{"text":"Which calendar date names this day?","kind":"definition"},{"text":"In which calendar?","kind":"definition"}]}]}]}]},"agentConduct":{"may":["Count days for durations and deadlines, stating the time zone and calendar.","Name dates and weekdays for its user."],"mustNot":["Assume every day has 24 hours across daylight saving changes.","Count calendar days where a rule specifies business days, or the reverse.","Shift an event to a different day through a time zone error without flagging it."],"requiresHuman":["Deciding whether a legal or contractual deadline has passed."]},"ethics":{"considerations":["Deadlines measured in days decide rights, payments and appeals.","Rest days and holy days matter to people and communities."],"affectedParties":["People with deadlines","Workers and their rest days","Religious communities"]},"owners":{"steward":"Nobody owns it; time authorities and governments set civil time and time zones.","roles":[],"masterSystems":[]},"relations":[{"target":"Q2199864","type":"parent","note":"registry parent class"},{"target":"unit of time","type":"related","note":"accepted for use with the SI"},{"target":"calendar date","type":"related","note":"a date identifies one day"},{"target":"hour","type":"related","note":"24 hours in civil time"},{"target":"daytime","type":"related","note":"daylight is only part of the day"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.day","Wikidata: Q573 (https://www.wikidata.org/wiki/Q573)","unit symbol: d accepted for use with the SI"]},"properties":{"applicability":"not-applicable","items":["length: 86400 s - SI day; mean solar day varies by milliseconds","sidereal day: 86164.09 s - rotation relative to the stars"]},"recognition":{"applicability":"optional","items":["Sunrise and sunset mark daylight, not the civil day","Calendars show days as dates and weekdays","Clocks reset at midnight in civil time","Experienced as daylight and night; recorded on clocks and calendars."]},"capabilities":{"applicability":"required","items":["count days, for durations and deadlines","name days, with calendar dates and weekdays","divide days, into hours, minutes and seconds","adjust them, as with leap seconds and daylight saving shifts"]},"hazards":{"applicability":"required","items":["Assuming every day has 24 hours across daylight saving changes","Confusing calendar days with business days in deadlines","Time zone errors that move events to another day"]},"interfaces":{"applicability":"required","items":["SI Brochure, non-SI units accepted for use","ISO 8601 for date and time representation","National laws on time zones and daylight saving"]},"context":{"applicability":"required","items":["Organising time for daily life, work, law and science.","solar day, sidereal day, civil day","working day, business day, calendar day","by name: weekdays"]}},"sources":[{"title":"Wikidata item Q573: day","url":"https://www.wikidata.org/wiki/Q573","note":"identity and sense of the item"},{"title":"Wikipedia: Day","url":"https://en.wikipedia.org/wiki/Day","note":"general description of the item"}],"openQuestions":["Should the civil day and the solar day be separate entries?","How should business days be modelled across jurisdictions with different holidays?","How should agents present day counts that cross time zones?"],"resources":{"spec":"/models/things/publications/thing-q573/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q573/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-09-11T04:26:34Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"not-applicable","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"filled"},"notes":{"_gate":"Published through the thing publication gate 1.0 on 2026-10-06T19:52:01+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass","interaction.properties":"Plane XCT: no invented physical properties."},"score":1.0}}