# subject (10-subject.com)

A subject is a topic or person being talked about. In school it is a field of study like math or history. In everyday talk it is whatever someone is focused on or describing.

## What a model may hear
- email subject line (email protocols and messaging systems): may parse, filter, or route based on the Subject header field
- grammatical subject (natural language processing and linguistics): may identify the noun phrase that performs the action in a sentence for parsing or translation
- security subject (access control and authentication systems): may check permissions, roles, or credentials bound to an entity
- experimental subject (research databases and clinical systems): may link to participant IDs, consent records, or trial data
- database subject (knowledge graphs and RDF/linked data): may treat as the URI or node that predicates describe in triple statements

## Where people and models part ways
- Says: "Change the subject"
  Means: Switch to a new topic of conversation
  May be taken as: May modify an email Subject header or alter a database subject node
  Say instead: "Let's talk about something else"
- Says: "Who is the subject of this photo"
  Means: Who is the main person shown
  May be taken as: May analyze grammatical structure or return metadata about image subjects in a dataset
  Say instead: "Who is the main person in this photo"
- Says: "The subject needs access"
  Means: This person needs permission to enter or use something
  May be taken as: May create or modify a security subject entity with role bindings
  Say instead: "This person needs permission to access this room or file"
- Says: "List all subjects"
  Means: Show all topics or people covered
  May be taken as: May query database subjects, email headers, or experimental participant tables
  Say instead: "List all topics we have discussed or all people mentioned"

## Tips
- Say 'topic' when you mean a theme or area of discussion
- Say 'person' or 'participant' when you mean a human being
- Say 'email heading' or 'title' when you mean the line above an email body
- Specify 'grammar' if you want linguistic analysis of who did what in a sentence
- Add 'in this conversation' or 'in this document' to keep the model's scope narrow

## Often confused with
- object: the thing acted upon, not the doer or topic
- topic: a theme without the grammatical or security baggage
- theme: a broader motif, not tied to grammar or identity systems
- participant: a person in a study, not a grammatical or security entity
- principal: a security identity, more specific than subject
- patient: the receiver of action in grammar, opposite of agent