Glossary

Glossary

This page defines the terms used across the fiscalclock wiki, README, spec and code; every other page uses these words with these meanings.

Last reviewed: 31 Oct 2026

Calendar concepts

Term	Meaning	Do not write
fiscal year	One year of an organisation's calendar, bounded by its year block.	"financial year" (except when quoting), "FY" as a noun in prose
fixed-date year	A fiscal year that starts on the same month and day every calendar year (year.type: "fixed_date").	"calendar-month year" when meaning the year type
week-based year	A fiscal year made of whole weeks whose boundary is set by an anchor rule (year.type: "week_based"); it has 364 or 371 days.	"52/53-week year" as a type name (fine as a description), "retail year"
table year	A fiscal year whose boundaries are listed explicitly (year.type: "table"); reserved for 0.2.	"irregular year"
anchor	The rule that fixes a week-based year's boundary: edge, month, day and rule.	"end rule"
last rule, first rule, nearest rule	The qualifying weekday on or before, on or after, or nearest to the target date.	"closest", "latest"
extra week	The 53rd week of a 371-day week-based year. Its placement is set by extra_week.	"leap week", "long week", "week 53" when the extra week is not numbered 53
has_extra_week	The output flag on a year, quarter or period that contains the extra week, and on the week that is the extra week.	is_long, is_53_week
period	The subdivision level below a quarter: a fiscal month in a calendar-month subdivision, or a group of weeks in a week pattern.	"fiscal month" as the level name (fine in prose for calendar months)
quarter	A group of consecutive periods given by subdivision.quarters. Quarters need not be equal.	"13-week quarter" as a definition
week	A 7-day block starting on week.starts_on; partial at the edges of a fixed-date year.
level	One of year, quarter, period, week.	"granularity"
coordinates	(level, year, index) identifying a period. year is the default scheme's year number.
week pattern	The weeks-per-period list in subdivision.periods, such as 4-5-4.	"445 calendar" as a type name
4-4-5 family	Week-based years whose quarters split 4-4-5, 4-5-4 or 5-4-4 weeks. Descriptive only; not an API name.
short_month	The policy (clamp or next) for a fixed-date start day that does not exist in a month.
stub	Partial weeks absorbed by the first and last periods of a fixed-date year with week-based periods; reserved, see ADR-0024.
special period	A zero-length ERP adjustment period such as SAP periods 13–16; reserved for 0.2.	"adjustment period" as the field name
transition year	A short or long year when an organisation changes its year end; reserved for 0.2.

Naming

Term	Meaning	Do not write
naming scheme	A named set of year_number, offset, century_pivot and templates. A calendar has one or more.	"label format"
default scheme	The scheme named by naming.default; it sets coordinates and is used by format when no scheme is given.
year number	The number a scheme gives a fiscal year: by start year, end year or majority year, plus offset.	"fiscal year label"
template	A label pattern such as FY{yyyy} Q{q}.	"format string"
label	A string produced by a template, such as "FY2026 Q3".
century pivot	The year that resolves two-digit years in parsing.	"reference year"

Engine and API

Term	Meaning	Do not write
definition	The JSON object describing a calendar (spec version 1).	"config", "preset"
block	One of the five top-level parts of a definition: year, week, subdivision, naming, exceptions.	"axis" in API text (fine in analysis prose)
canonical form	The definition serialised with sorted keys, defaults written out and no whitespace.
calendar_id	The first 16 hex characters of the SHA-256 of the canonical form.	"calendar hash"
civil date	A date with no time or zone, proleptic Gregorian.	"naive date"
half-open interval	[start, end_exclusive); last_day is derived.	"inclusive end" without end_exclusive
supported range	Fiscal years lying wholly between 0001-01-02 and 9999-12-30.
error code	The stable code of an error, such as WEEKS_SUM_MISMATCH.	"error type"
core	The Rust crate fiscalclock in crates/core, where all logic lives.	"engine library"
binding	A thin package (Python, npm) that converts native types and calls the core's JSON API.	"port", "wrapper library"
conformance vector	A JSON file of definition, inputs and expected outputs shared by all test suites.	"fixture"
oracle	An independent source of expected results: a standard library, a published calendar, a filing or another implementation.
reference implementation	The deliberately slow day-by-day implementation used in differential tests.
registry	The separate, versioned repository of cited real-world definitions. Not part of any package API.	"presets"
JSON API	The core's text-in, text-out functions fiscalclock::json::validate and fiscalclock::json::call, which every binding calls.	"FFI layer"
transcript	A file with one line of raw JSON output per conformance case, written by each language's conformance runner (rust.txt, python.txt, js.txt).	"snapshot"
cross-binding identity	The property that every binding, on every platform, returns the core's JSON byte for byte; CI checks it by comparing transcripts.	"parity"
differential test	A test that compares the core with the reference implementation over a range of dates.
property test	A test that checks a rule, such as tiling, over randomly generated definitions and dates.
explain	The operation that returns the step-by-step rule trace for a date. Its wording is not part of the API.
smoke test	A short check that a built package installs and returns a known result.
provenance attestation	A signed record, made by the release workflow, of which commit and workflow built an artefact.
MCP	Model Context Protocol, the protocol the planned server uses to offer fiscalclock tools to agents.

Project process

Term	Meaning
phase	One of Phase 0 to Phase 5 on the Roadmap. Names: "Phase 0: Foundations", "Phase 1: v0.1", "Phase 2: v0.2", "Phase 3: v0.3", "Phase 4: v0.4", "Phase 5: v1.0".
gate	The checks that close a phase: Gate A (Phase 0) to Gate E (Phase 4).
ADR	Architecture Decision Record, in MADR format. Status is Proposed, Accepted, Rejected or Superseded.
Decided	Settled by the research documents or by an Accepted ADR.
built	Implemented and tested in a release that exists, currently 0.1.0.
planned	Designed and scheduled on the Roadmap, but not implemented.
unverified	A claim with no confirmed source yet; written as an open question or marked as such.
delegation	The maintainer's request that the roadmap and 0.1.0 be decided and built without them; ADRs decided this way say so in their status.
Proposed	An open decision awaiting discussion.
illustrative	An example not checked against its source; never used as a conformance vector until checked.