# Glossary
> The words Terra uses, from Agent to Zen mode, each explained in a sentence or two with a link to the page that covers it.
Source: https://terramd.io/docs/glossary
Terra has a few words of its own, and uses some familiar ones in a particular way. Here they are from A to Z. Coming from Obsidian? A Library is what Obsidian calls a vault, and a Sprout is a callout.
## Agent
Terra Agent is the AI assistant built into Terra. It answers questions from your notes, with links to the ones it used, and can create or edit notes when you allow it. It runs on an AI provider you connect, such as Claude, OpenAI or Gemini. See [Ask your Library](https://terramd.io/docs/ask-your-library).
## Annotation
A highlight, a note on a passage or a bookmark you add while reading. For EPUB books, Terra keeps annotations in the book's [sidecar](#sidecar) and never changes the book; PDF highlights are written into the PDF itself. See [Highlights and annotations](https://terramd.io/docs/annotate-in-the-sidecar).
## Attachment
A file that belongs to a note, such as an image you pasted or a document you dropped in. Terra copies it into an `attachments` folder beside the note, and the note links to it. See [How Terra stores your notes](https://terramd.io/docs/how-terra-stores-your-notes).
## Backlink
A link to the note you're looking at, from another note. The **Backlinks** button above a note's text counts them; click it to see where they come from. See [Links and backlinks](https://terramd.io/docs/links-and-backlinks).
## Block
One piece of a note: a paragraph, a heading, a list item, a quote, a [Sprout](#sprout), a table, an image or a code block. Point at a block to show its handle in the margin; drag the handle to move the block, or click it for **Turn into**, **Toggle**, **Copy link to block**, **Copy as**, **Duplicate** and **Delete**. See [Advanced formatting](https://terramd.io/docs/advanced-formatting).
## Canvas
A free-form board where you place notes, sticky notes, text, shapes and images, and draw connections between them. Canvases you make are listed under **Canvases** in the sidebar, and a [database](#database) can be laid out as a canvas too. See [Canvas, mind maps and the graph](https://terramd.io/docs/canvas-and-mind-maps).
## Capture
Saving something into Terra in a couple of seconds, from any app: press ⌃ ⌥ ⌘ N, or choose **File › Quick Capture…**, and the capture lands in your [Inbox](#inbox). With enrichment on, Terra can also tidy it into a [template](#template) and sort it into categories you choose. See [Capture and classify](https://terramd.io/docs/capture-and-classify).
## Command palette
The search box that runs any command by name. Press ⌘ K and type: it lists commands with their shortcuts, notes whose titles match, and answers from Terra's Help. See [Find your way around](https://terramd.io/docs/find-your-way-around#command-palette).
## Connector
A connection to an outside service, set up in **Settings › Integrations**: Google Calendar, Granola, Slack, GitHub, Jira and Confluence. Depending on the service, its items can appear inside your notes, arrive as notes of their own or, for Google Calendar, show on the Calendar. Keys are kept in your Mac's Keychain. See [Bring in meetings from Granola](https://terramd.io/docs/meeting-notes#bring-in-meetings-from-granola-optional) for one example.
## Dashboard
A note that puts live views of your databases on one page, such as a count, a chart, a table and a board. The **Dashboard** template starts one for you. See [Build a dashboard](https://terramd.io/docs/dashboards).
## Database
A live collection of the notes that match a set of conditions, such as every note in a folder or every note with a tag. Each note is a row and its [properties](#property) are the columns. Nothing is copied: the rows are your notes. See [Databases](https://terramd.io/docs/databases).
## Drawer
A panel that opens beside your panes. **Properties** in the toolbar opens the drawer on the right, with sections for the open note's properties, comments, versions and more; **AI conversations** opens the chat; **Database drawer** is the note list. See [Find your way around](https://terramd.io/docs/find-your-way-around#drawers).
## Embed
Something shown inside a note rather than linked: another note, written `![[Note title]]`, a view of a database, inserted with `/database`, or an item from a [connector](#connector). See [Advanced formatting](https://terramd.io/docs/advanced-formatting).
## Favorites
Notes you've marked with **Add to Favorites**, the flag in the editor toolbar. They're listed under **Favorites** in the sidebar, and you can sort them into favorites collections without moving the files. See [Files and folders](https://terramd.io/docs/files-and-folders).
## Filter
A condition that narrows a database view to the notes you want, such as *status is Done* or *tags contain launch*. Each [view](#view) keeps its own filters. See [Filter, sort and group](https://terramd.io/docs/filter-sort-and-group).
## Folder
A real folder inside your Library folder. The **Folders** section of the sidebar shows the same tree you'd see in Finder, and clicking a folder shows its notes. See [Files and folders](https://terramd.io/docs/files-and-folders).
## Formula
A computed [property](#property) in a database you made: an expression, much like a spreadsheet formula, that Terra works out for each row from its other properties. In a table inside a note, a cell that starts with `=`, such as `=SUM(above)`, is a formula too. See [Formulas, threads and gathers](https://terramd.io/docs/formulas-threads-and-gathers).
## Frontmatter
The block of properties at the top of a note's Markdown file, written in YAML between two lines of three dashes. Terra keeps a note's id, title, dates, tags and other [properties](#property) there. See [Properties](https://terramd.io/docs/properties).
## Gather
A computed property that reads through a [thread](#thread) and totals, counts or picks values from the notes it links to, such as the total effort of a milestone's work items. You write it as one function, such as `SUM(@work.@effort)`. See [Formulas, threads and gathers](https://terramd.io/docs/formulas-threads-and-gathers).
## Inbox
The `Inbox` folder in your Library, where new notes and quick captures land. It's also listed under **Databases** in the sidebar. See [Files and folders](https://terramd.io/docs/files-and-folders).
## Layout
How a database [view](#view) arranges its notes: **Table**, **Board**, **List**, **Cards**, **Feed**, **Calendar**, **Timeline**, **Map**, **Graph**, **Canvas**, **Chart** or **Form**. Layouts such as **Side by side** and **2 × 2** also arrange the [panes](#pane) in the window. See [Views and layouts](https://terramd.io/docs/views-and-layouts).
## Library
A folder on your Mac that Terra treats as one collection of notes, with its own settings, databases and templates. Any folder can be a Library, including an Obsidian vault. See [Libraries](https://terramd.io/docs/libraries).
## Note
A Markdown file in your Library, with a short header of [frontmatter](#frontmatter) at the top. PDFs, books, images and spreadsheets you add get a note of their own, too. See [Files and folders](https://terramd.io/docs/files-and-folders).
## Outline
The list of a note's headings shown at the right of the note when the pane has room. Click a heading to jump to it. **Settings › Appearance › Note outline** switches it between **Table of contents**, **Minimap** and **None**, and ⇧ ⌘ O shows or hides it. See [Make Terra yours](https://terramd.io/docs/make-terra-yours).
## Pane
A tile in the main part of the window that holds [tabs](#tab). A window can show up to four panes side by side or stacked. See [Find your way around](https://terramd.io/docs/find-your-way-around#split-panes).
## Peek
A note shown over the pane you're in, so you can look at it without losing your place. Clicking a row in a database opens a peek; you can dock it left, right, center or at the bottom. See [Find your way around](https://terramd.io/docs/find-your-way-around#peek).
## Property
A named value on a note, such as a status, a due date or an owner. Properties appear under the note's title and are saved in its [frontmatter](#frontmatter), and databases can sort, filter and group by them. See [Properties](https://terramd.io/docs/properties).
## Query
A saved question about your Library, written in SQL and listed under **Queries** in the sidebar. You can also describe what you want in plain English and let Terra write the SQL, if you've connected an AI provider. See [Queries](https://terramd.io/docs/queries).
## Rail
The slim column of icons that replaces the sidebar when you hide it or the window gets narrow. It keeps **All notes**, **Tasks**, **Calendar** and anything you've pinned within reach. See [Find your way around](https://terramd.io/docs/find-your-way-around#sidebar).
## Reader
Terra's e-reader for EPUB books and PDFs, with your own theme, font and layout, and your place remembered in every book. A note's **Read** mode is something else: it shows the note without editing. See [Read comfortably in the e-reader](https://terramd.io/docs/read-in-the-e-reader).
## Recipe
One of the [templates](#template) Terra puts in every Library. It turns a recipe note, such as a captured web page, into a tidy one: the title, a link to the source, the first picture, the ingredients in a [Sprout](#sprout) and the directions as a numbered list. See [Capture and classify](https://terramd.io/docs/capture-and-classify).
## Shelf
A strip at the foot of the window for panes you've set aside with **Minimize to shelf**. Click a pane on the shelf to bring it back. See [Find your way around](https://terramd.io/docs/find-your-way-around#shelf).
## Sidecar
A file next to a note or book, with the same name and the ending `.terra.json`, where Terra keeps what Markdown can't hold: a book's highlights and reading position, a table's formulas, comments, a Sprout's properties. Most notes don't have one. If you move a note in Finder, move its sidecar with it. See [How Terra stores your notes](https://terramd.io/docs/how-terra-stores-your-notes).
## Slash menu
The menu that opens when you type `/` in a note. It lists blocks you can insert, such as headings, lists, [Sprouts](#sprout), tables, code and math; keep typing to narrow it down. The **+** button in the editor toolbar opens it too. See [Basic formatting syntax](https://terramd.io/docs/formatting-syntax).
## Sprout
A coloured box in a note that makes a point stand out, such as a tip or a warning. It's written like an Obsidian callout, `> [!tip] Title`, and can carry its own properties. Every Sprout in the Library also appears in **Sprouts** in the sidebar. See [Sprouts](https://terramd.io/docs/sprouts).
## Status
A property type for where something stands. Each option belongs to a group, **To do**, **In progress** or **Done**, so databases know what's finished; a new Status property starts with **Not started**, **In progress** and **Done**. [Tasks](#task) have their own statuses, written in the checkbox: `[ ]` open, `[/]` in progress, `[x]` done, `[-]` cancelled. See [Properties](https://terramd.io/docs/properties) and [Task syntax](https://terramd.io/docs/task-syntax).
## Tab
One open item in a [pane](#pane): a note, a database, a web page or Help. Right-click a tab to close it, close the others or pin it. See [Find your way around](https://terramd.io/docs/find-your-way-around#panes-and-tabs).
## Tag
A short label such as `#reading` that gathers notes from different folders. Write it in the text or add it to the note's **tags** property; either way the note shows up on the tag's page and in tag searches. See [Tags](https://terramd.io/docs/tags).
## Task
A checkbox line in a note, such as `- [ ] Book the projector`. Terra gathers every task in the Library into **Tasks**, where you can set due dates and change status, and the line in the note changes to match. See [Tasks](https://terramd.io/docs/tasks).
## Template
A note that new notes start from, with placeholders such as `{{ title }}` and properties of its own. Every Library starts with a few, including Daily log, Meeting, Project, Decision and [Recipe](#recipe). Choose **File › New from Template…** to use one. See [Templates](https://terramd.io/docs/templates).
## Thread
A computed property that links a note to other notes, such as work items to their milestone. You pick the notes, or let conditions pick them. Terra saves the links in the note's `relations` property, and [gathers](#gather) and timelines can follow them. See [Formulas, threads and gathers](https://terramd.io/docs/formulas-threads-and-gathers).
## Toggle
A block you can fold. Folding a toggle hides what belongs to it: a heading's section, a list item's nested items, a quote's or Sprout's body, or everything after the first line of a paragraph. Turn one on with **Toggle** in the block menu, or press ⌥ ⌘ 7. See [Keyboard shortcuts](https://terramd.io/docs/keyboard-shortcuts#text).
## Trash
Where deleted notes go, in a `Trash` folder in your Library. Right-click a note there and choose **Put Back** to restore it. By default, Terra empties notes that have been in the Trash for 30 days, and emptying is permanent. See [Files and folders](https://terramd.io/docs/files-and-folders).
## Type
A property that says what kind of thing a note is, such as `project`, `meeting` or `contact`; you choose the names. A type can use one of Terra's models (Person, Article, Book, Location, Group, Event, Plan or Medium), which decides how its cards look. Not to be confused with a property's type, such as Text or Date. See [Properties](https://terramd.io/docs/properties).
## Versions
Terra's history of your notes, built on git. Click **Save version** to record how the Library's notes are now, then compare or restore any note from an earlier version, or send the history to a Git server. It's off until you turn it on. See [Sync and back up](https://terramd.io/docs/sync-and-back-up).
## View
A saved way of looking at a [database](#database): a [layout](#layout) plus its filters, sort, grouping and visible properties. One database can have many views of the same notes. The **Views** section of the sidebar is different: it saves arrangements of panes. See [Views and layouts](https://terramd.io/docs/views-and-layouts).
## Wiki-link
A link to another note, written in double square brackets: `[[Printer quotes]]`, the same as in Obsidian. Terra shows it as a chip with the note's title, and updates it when you rename the note. Type `@` and pick a note to insert one. See [Links and backlinks](https://terramd.io/docs/links-and-backlinks).
## Zen mode
A way to clear the window down to your panes. Press ⌥ ⌘ Z to hide the sidebar, note list and drawers, and again to bring them back. See [Find your way around](https://terramd.io/docs/find-your-way-around#zen-mode).
## Related
- [Get started with Terra](https://terramd.io/docs/quickstart): the basics, step by step.
- [Find your way around](https://terramd.io/docs/find-your-way-around): every part of the window.
- [Keyboard shortcuts](https://terramd.io/docs/keyboard-shortcuts): every key.