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year

vr.tr.year · thing-q577

Let an agent handle years by definition (calendar, tropical, fiscal, academic), calendar system and numbering, and avoid errors from mismatched year definitions.

Thing Registry Cross-cutting context XCT.TME
Bundle → Layer → Finding → QuestionsClassifiersWhat it isWhy it existsDistinguishing featuresWhat robots and AI may and may not doMoral aspectsOwnersLinks to other meta-modelsIdentity and identifiersDirect propertiesRecognitionCapabilities and actionsHazards and failure modesStandards and interfacesContext of useSources

Bundle → Layer → Finding → Questions Filled

4 bundles · 8 layers · 8 findings · 16 questions

Definition Which year.

Kind

Calendar, fiscal, academic, astronomical.

Year kind

The kind of year.

  1. Which kind of year is meant here? definition
  2. When does it start and end? boundary

Calendar

Gregorian or other.

Calendar

The calendar used.

  1. In which calendar is this year counted? definition
  2. What is its Gregorian equivalent? measurement
Length Days in the year.

Leap years

Rules.

Leap rule

The leap rule.

  1. Is this a leap year under the applicable rule? measurement
  2. How is 29 February handled in this system? boundary

Duration

Astronomical lengths.

Duration

Which length is used.

  1. Which year length does this calculation assume? definition
  2. How much error does that introduce? measurement
Numbering Eras and names.

Era

CE, AH, other eras.

Era

The era and numbering.

  1. In which era is the year numbered? definition
  2. Is there a year zero in this system? boundary

Names

Cyclical names.

Year names

Names in cyclical calendars.

  1. What is the name of this year in the relevant cyclical calendar? definition
  2. When does that year begin? measurement
Use Years in law, business and software.

Fiscal and academic years

Institutional years.

Institutional year

The institutional year definition.

  1. Which fiscal or academic year applies, and how is it labelled? definition
  2. Who defines it? provenance

Software limits

Date limits and bugs.

Software limits

Known year-related limits.

  1. Does the system handle leap years and dates beyond 2038 correctly? boundary
  2. How is the year stored? definition

Classifiers Filled

Family
Thing Registry
Category
Cross-cutting context
Entry kind
thing
Plane
XCT
Domain
XCT.TME
Other names and narrower kinds
even year, odd year, century year, commemorative year, educational year, level of education in France, Yang Metal Dragon, FRBR equinox, year of multiple elections, vintage year, model year, tropical year

What it is Filled

The time the Earth takes to orbit the Sun, about 365.24 days, and the calendar unit of 365 or 366 days based on it; also used for other year definitions such as school or fiscal years.

Why it exists Filled

Let an agent handle years by definition (calendar, tropical, fiscal, academic), calendar system and numbering, and avoid errors from mismatched year definitions.

Distinguishing features Filled

  • Several definitions: tropical, sidereal, calendar, fiscal, academic
  • Calendar years depend on the calendar system
  • Leap years keep the calendar aligned with seasons
  • Some systems name years instead of numbering them

What robots and AI may and may not do Filled

Must not

  • Mix calendar and fiscal years without saying so.
  • Store years in a way that overflows or wraps, such as two-digit years or limited time counters.
  • Convert historical years across calendar reforms without stating the calendar used.

Only with a human decision

  • Changing year-end dates used for legal or financial deadlines.

May

  • Calculate dates and durations with correct leap year rules.
  • State which year is meant: calendar, fiscal, school or another.

Moral aspects Filled

  • Deadlines tied to years decide rights, benefits and penalties.

Who is affected

  • People with year-based deadlines
  • Users of software

Owners Filled

Steward

Nobody owns the year; standards bodies define calendars and date formats.

Links to other meta-models Filled

parent

  • Q186081 - registry parent class
  • Q2199864 - registry parent class
  • Q37640 - registry parent class

related

  • day - 365 or 366 days
  • calendar - calendar system
  • fiscal year - business and government years differ
  • calendar date - the year component of dates

What else AI and robots need to interact with it Filled

Identity and identifiers required Filled

  • Vercy registry: vr.tr.year
  • Wikidata: Q577 (https://www.wikidata.org/wiki/Q577)
  • ISO 8601 year: YYYY with extended forms for years outside 0000-9999

Direct properties not applicable Not applicable

  • tropical year: 365.2422 days
  • Gregorian calendar year: 365 or 366 days
  • Julian year (astronomy): 365.25 days - used for light years

Plane XCT: no invented physical properties.

Recognition optional Filled

  • Four-digit year numbers in the Gregorian calendar
  • Fiscal and academic year labels spanning two calendar years
  • Names in cyclical calendars
  • Not a thing to see; shown as a number (2026), a label (FY2026/27) or a name in some calendars (such as Yang Metal Dragon in the Chinese cycle).

Capabilities and actions required Filled

  • count and number years, in a calendar era
  • define custom years, such as fiscal or academic
  • convert between calendars
  • account for leap years

Hazards and failure modes required Filled

  • Mixing calendar and fiscal years
  • Leap year bugs such as 29 February handling
  • Year 2038 and similar overflow limits in software
  • Converting historical years across calendar reforms

Standards and interfaces required Filled

  • ISO 8601
  • National laws defining fiscal years
  • IAU definitions of Julian year

Context of use required Filled

  • Organising time into seasons and annual cycles for law, business, education and culture.
  • calendar year
  • tropical and sidereal year
  • fiscal year
  • academic or school year
  • leap year, even and odd years, century years
  • commemorative years

Sources Filled

  1. Wikidata item Q577: year - identity and sense of the item
  2. Wikipedia: Year - general description of the item

Open questions

  • Should each kind of year be a separate entry?
  • How should fiscal years be recorded per organisation and country?
  • How should cyclical year names be linked to numbers?

Machine files

Card as JSON Specification Card backlog vercy.card/1

Provenance

thing registry research (pass 2) · unreviewed

Built from: models/things/publications/thing-q577/spec.json