# Domain Glossary

## Merchant

A business represented in the source data. A merchant owns terminals, payment sessions, and merchant users. In the MVP, detailed data is visible only within that merchant's authenticated boundary.

## Merchant User

A person/account permitted to authenticate as one merchant. The hackathon seed creates an initial demo user for each merchant; a merchant and a merchant user are not the same concept.

## Terminal

A merchant-owned payment endpoint identified by the source terminal key.

## Payment Session

One payment journey identified by the source session key. A session belongs to one merchant and terminal and can contain one or more payment attempts.

## Payment Attempt

One try within a payment session, distinguished by its try sequence. This is the grain of a source CSV row and must not be confused with a unique payment session.

## Opaque Payer Token

The nullable `payer_card_key` source value. It is an unverified, merchant-scoped token used only for internal approximate repeat-payer analytics. It is not a card number or verified person identifier.

## Import Run

One traceable attempt to ingest a specific source archive/schema using a specific importer revision. It records outcome, counts, validation evidence, and provenance.

## Calendar Date

One civil date enriched with Gregorian and Jalali calendar attributes, Persian month/season, weekday, and reporting attributes.

## Reporting Period

An approved time window used for metrics: Tehran-local day, week, Jalali month, or Persian season.

## Analytical Metric

A deterministic numerical measure with a definition, source fields, filters, period, unit, missing-data behavior, and drill-down path.

## Analytics Projection

A rebuildable, versioned analytics result derived from normalized PostgreSQL facts and cached in Redis for one merchant/cohort revision. It is not independent business truth.

## Analytics Revision

A monotonically increasing PostgreSQL merchant or cohort version changed when a related payment fact is inserted. Redis cache keys include the revisions they represent; a mismatch causes request-triggered section jobs to calculate new keys while older keys expire through TTL.

## Analytics Section

One independently calculable and deliverable dashboard part. The MVP section ids are `overview`, `payment_performance`, `fees`, and `peer_comparison`. All four start on first dashboard access and become visible independently through authenticated SSE events.

## Peer Cohort

An approved group of other merchants used for anonymized comparison. The active merchant is excluded, and a benchmark is suppressed unless at least 10 peers and 1,000 peer sessions contribute.