# Glossary

**Related Documents**:
- [Existing Code](./existing-code.md) - Current codebase
- [Lexicon Schemas](../data/lexicon-schemas.md) - AT Protocol terms

## AT Protocol / Bluesky Terms

### AT Protocol (ATProto)
The underlying protocol for Bluesky and other federated social apps. Provides authentication, data storage, and federation capabilities.

### PDS (Personal Data Server)
A server that stores a user's personal data in the AT Protocol network. Users can host their own PDS or use a provider like Bluesky.

### DID (Decentralized Identifier)
A unique identifier for users in AT Protocol. Format: `did:plc:abc123...`

### Lexicon
A schema definition that describes the structure of records, queries, procedures, and subscriptions in AT Protocol.

### NSID (Namespaced Identifier)
A unique identifier for lexicons using reverse-DNS notation. Example: `social.drydown.review`

### Record
Data stored in a user's repository. Examples: posts, profiles, follows, and custom data like fragrance reviews.

### Repository (Repo)
A user's collection of records in their PDS. Organized by collection type (NSID).

### Collection
A namespace for related records. Example: `social.drydown.review` is a collection of fragrance review records.

### TID (Timestamp Identifier)
A timestamp-based unique identifier for records. Used as the default key for records.

### Rkey (Record Key)
The unique identifier within a collection for a specific record. Can be a TID or a fixed value like "self".

### OAuth 2.0
Authentication protocol used by AT Protocol for user authorization.

### DPoP (Demonstrating Proof of Possession)
A security mechanism that binds access tokens to a specific client, preventing token theft.

### Agent
An API client instance (`@atproto/api`) authenticated with a user's session. Used to make API calls.

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## Fragrance Terms

### Sillage
The trail of scent left behind by a fragrance. Also called "projection over distance."

### Longevity
How long a fragrance lasts on the skin before becoming undetectable.

### Projection
How far a fragrance projects from the body. Similar to sillage but measured closer to the wearer.

### Top Notes
The initial scents perceived immediately after application (0-15 minutes). Usually lighter, more volatile compounds.

### Heart Notes (Middle Notes)
The scents that emerge after top notes fade (15 minutes - 4 hours). The "character" of the fragrance.

### Base Notes
The lasting scents that appear after 4+ hours. Usually heavier, longer-lasting compounds.

### Drydown
The final stage of a fragrance's development when only base notes remain. Also the name of this app!

### Skin Chemistry
How a fragrance interacts with an individual's skin pH, oils, and body chemistry. The same fragrance can smell different on different people.

### Complexity
How many distinct notes or layers a fragrance has. A complex fragrance evolves over time with multiple facets.

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## App-Specific Terms

### Stage 1 (Initial)
The first rating stage capturing top notes and first impressions (0-2 hours).

### Stage 2 (Heart)
The second rating stage capturing middle notes (2-4 hours after application).

### Stage 3 (Final)
The third rating stage capturing base notes, longevity, and overall experience (4+ hours after application).

### In-Progress Review
A review that hasn't completed all required stages yet. Stored in LocalStorage.

### Completed Review
A review with all required stages finished. Stored in AT Protocol repository.

### Calculated Rating
The final weighted average rating (0-5, to 3 decimal places) based on all stage ratings and user's custom weights.

### Rating Weights
User-configurable values (0-10) that determine how much each rating criterion affects the final calculated rating.

### Grapheme
A user-perceived character. Used for text length counting. Examples: "a" = 1 grapheme, "👍" = 1 grapheme, "👨‍👩‍👧‍👦" = 1 grapheme (family emoji).

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## Technical Terms

### LocalStorage
Browser-based storage for client-side data. Used for in-progress reviews in Drydown.

### Context API
React/Preact pattern for passing data through the component tree without prop drilling.

### Hooks
React/Preact functions that let you use state and lifecycle features in function components. Examples: `useState`, `useEffect`, `useContext`.

### SPA (Single Page Application)
A web app that loads a single HTML page and dynamically updates content without full page reloads.

### OAuth Client
The application requesting authorization (Drydown). Receives access tokens after user approval.

### OAuth Session
An authenticated session containing access tokens and user information.

### Bundle Size
The total size of JavaScript/CSS files sent to the browser. Smaller is better for performance.

### Code Splitting
Breaking JavaScript into smaller chunks loaded on demand, improving initial load time.

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## Development Terms

### MVP (Minimum Viable Product)
The simplest version of the product with core features. For Drydown: three-stage reviews, rating calculation, and Bluesky sharing.

### P0/P1/P2 (Priority Levels)
- **P0**: Must-have for MVP (launch blocker)
- **P1**: Important for good UX (launch soon after MVP)
- **P2**: Nice-to-have (can launch without)

### Phase
A logical grouping of features for implementation. Drydown has 4 phases.

### Status Indicators
- 🔴 Planned - Not started
- 🟡 In Progress - Actively being worked on
- 🟢 Implemented - Complete and tested
- 🔵 Documented - Implemented with full documentation

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**Related Documents**:
- [Product Features](../product/features.md) - Feature definitions using these terms
- [Lexicon Schemas](../data/lexicon-schemas.md) - AT Protocol technical details
- [Requirements](../product/requirements.md) - Detailed specifications