# Chat and Messaging Glossary

> 39 terms from the Workplace & Collaboration book's Chat and Messaging part, each defined in a line and linked to the chapter that explains it.

- **Availability view:** A string from Microsoft Graph's getSchedule with one digit per time slot (free, tentative, busy, out of office, working elsewhere) describing a person's or room's free/busy ([Email & Calendar](https://www.syntaqx.com/books/workplace-and-collaboration/email-and-calendar#free-busy-and-availability)).
- **Broadcast mention:** A mention such as `@channel`, `@here` or `@everyone` that notifies every member (or every active member) of a container, gated by permissions and size thresholds ([Notifications, Presence & Attention](https://www.syntaqx.com/books/workplace-and-collaboration/notifications-and-attention#channel-wide-mentions)).
- **CalDAV:** The IETF protocol (RFC 4791) for accessing and managing iCalendar data over WebDAV, extended by RFC 6638 for server-side scheduling ([Email & Calendar](https://www.syntaqx.com/books/workplace-and-collaboration/email-and-calendar#caldav-and-implicit-scheduling)).
- **Canvas:** A formatted document embedded in a chat channel or DM, with its own edit and comment permissions ([Channels, Threads & Direct Messages](https://www.syntaqx.com/books/workplace-and-collaboration/workplace-chat#canvases-lists-and-huddles)).
- **Cell (availability zone):** A siloed copy of a service stack in one availability zone that receives and sends traffic only within the zone, so the zone can be drained without user-visible errors ([Chat at Scale](https://www.syntaqx.com/books/workplace-and-collaboration/chat-architecture#cells-and-draining)).
- **Channel server:** In Slack's architecture, a stateful in-memory service that owns a consistent-hashed set of channels and fans their messages out to gateway servers ([Chat at Scale](https://www.syntaqx.com/books/workplace-and-collaboration/chat-architecture#the-write-path-at-slack)).
- **Compliance copy:** A copy of a chat message stored for search, hold and export separately from the chat service's primary store, as Teams does in participants' and group mailboxes ([Chat at Scale](https://www.syntaqx.com/books/workplace-and-collaboration/chat-architecture#teams-a-chat-service-and-a-record-in-every-mailbox)).
- **Constructive knowledge:** Under the FLSA, what an employer should have known about unscheduled work through reasonable diligence, which makes that work compensable ([Frontline & Deskless Workers](https://www.syntaqx.com/books/workplace-and-collaboration/frontline-workers#after-hours-messages-and-wage-hour-law)).
- **Do not disturb:** A member state that suppresses notification banners and sounds while still delivering messages, with bounded breakthrough for urgent senders or a priority list ([Notifications, Presence & Attention](https://www.syntaqx.com/books/workplace-and-collaboration/notifications-and-attention#do-not-disturb-schedules-and-breakthrough)).
- **Free/busy:** Time ranges and a busy status for a calendar, shared without event details, used to find meeting times ([Email & Calendar](https://www.syntaqx.com/books/workplace-and-collaboration/email-and-calendar#free-busy-and-availability)).
- **Frontline Member:** Slack's restricted, lower-priced account type for deskless employees, limited to channels admins add them to and billed on everyone added ([Frontline & Deskless Workers](https://www.syntaqx.com/books/workplace-and-collaboration/frontline-workers#restricted-seats)).
- **Frontline worker:** An employee who works mostly away from a desk, on phones or shared devices, often in shifts and often paid hourly ([Frontline & Deskless Workers](https://www.syntaqx.com/books/workplace-and-collaboration/frontline-workers)).
- **Group DM:** A direct message conversation among a small fixed set of people, without a name or owner, such as Slack's DMs of up to nine people ([Channels, Threads & Direct Messages](https://www.syntaqx.com/books/workplace-and-collaboration/workplace-chat#direct-messages-and-group-chats)).
- **Huddle:** Slack's informal audio and video call started in a channel or DM, with its own notes thread and canvas ([Channels, Threads & Direct Messages](https://www.syntaqx.com/books/workplace-and-collaboration/workplace-chat#canvases-lists-and-huddles)).
- **iCalendar:** The IETF data format (RFC 5545) for events, to-dos, free/busy and time zones, the interchange format for meeting invitations ([Email & Calendar](https://www.syntaqx.com/books/workplace-and-collaboration/email-and-calendar#the-calendar-standards)).
- **ID-only push notification:** A push that carries only a message id, with the app fetching content from the server on receipt, keeping content out of Apple's and Google's push services ([Notifications, Presence & Attention](https://www.syntaqx.com/books/workplace-and-collaboration/notifications-and-attention#push-through-someone-else-s-pipe)).
- **iMIP:** The binding (RFC 6047) that carries iTIP scheduling messages in email, with rules for authenticating organizers and attendees ([Email & Calendar](https://www.syntaqx.com/books/workplace-and-collaboration/email-and-calendar#itip-the-organizer-owns-the-event)).
- **Implicit scheduling:** CalDAV scheduling in which the server sends invitations, replies and cancellations when a client saves an event ([Email & Calendar](https://www.syntaqx.com/books/workplace-and-collaboration/email-and-calendar#caldav-and-implicit-scheduling)).
- **In-line thread:** A side conversation branching from one message in a space, as in Google Chat since 2022, notifying participants and followers ([Channels, Threads & Direct Messages](https://www.syntaqx.com/books/workplace-and-collaboration/workplace-chat#in-line-threads-in-google-chat)).
- **iTIP:** The scheduling protocol (RFC 5546) defining methods such as REQUEST, REPLY, CANCEL and COUNTER and how updates are ordered by UID, SEQUENCE and DTSTAMP ([Email & Calendar](https://www.syntaqx.com/books/workplace-and-collaboration/email-and-calendar#itip-the-organizer-owns-the-event)).
- **JSCalendar:** A JSON data model for calendar data (RFC 8984), compatible with iCalendar and intended to succeed it over time ([Email & Calendar](https://www.syntaqx.com/books/workplace-and-collaboration/email-and-calendar#jscalendar-and-the-json-future)).
- **Messaging policy:** A tenant-level policy, assignable to users or groups, that decides who can edit or delete sent messages, use broadcast mentions and see read receipts ([Channels, Threads & Direct Messages](https://www.syntaqx.com/books/workplace-and-collaboration/workplace-chat#editing-and-deleting-the-admin-s-decision)).
- **Predictive scheduling law:** A law requiring advance publication of work schedules, rest between shifts and premium pay for late changes, such as Oregon's 14-day notice rule ([Frontline & Deskless Workers](https://www.syntaqx.com/books/workplace-and-collaboration/frontline-workers#predictive-scheduling-laws)).
- **Presence:** A derived signal of a member's availability (available, busy, away, do not disturb, offline) computed from activity, app state and the calendar across devices ([Notifications, Presence & Attention](https://www.syntaqx.com/books/workplace-and-collaboration/notifications-and-attention#presence)).
- **Presence session:** One client's or app's contribution to a user's presence, which expires unless refreshed and is aggregated with the others ([Notifications, Presence & Attention](https://www.syntaqx.com/books/workplace-and-collaboration/notifications-and-attention#presence)).
- **Priority access:** A Teams list of people whose messages and calls break through a user's do-not-disturb state ([Notifications, Presence & Attention](https://www.syntaqx.com/books/workplace-and-collaboration/notifications-and-attention#do-not-disturb-schedules-and-breakthrough)).
- **Push-to-talk:** Walkie-talkie style voice over Wi-Fi or cellular data on phones, using chat channels as talk groups, as in Teams Walkie Talkie ([Frontline & Deskless Workers](https://www.syntaqx.com/books/workplace-and-collaboration/frontline-workers#push-to-talk)).
- **Read marker:** The server-side record of the last message a member has read in a channel or followed thread, from which unread and badge counts are derived ([Chat at Scale](https://www.syntaqx.com/books/workplace-and-collaboration/chat-architecture#ordering-unread-state-and-badges)).
- **Resource mailbox:** An Exchange mailbox for a room or piece of equipment whose calendar processing rules accept, decline or route bookings ([Email & Calendar](https://www.syntaqx.com/books/workplace-and-collaboration/email-and-calendar#rooms-and-resources)).
- **Right to disconnect:** A legal rule on work contact outside working hours, ranging from a written-policy duty (Ontario) to a right to refuse unreasonable contact (Australia) ([Notifications, Presence & Attention](https://www.syntaqx.com/books/workplace-and-collaboration/notifications-and-attention#the-right-to-disconnect)).
- **Scheduling link:** A booking page that publishes a host's availability from connected calendars and creates the event when a guest picks a slot ([Email & Calendar](https://www.syntaqx.com/books/workplace-and-collaboration/email-and-calendar#scheduling-links)).
- **Shared device mode:** A Microsoft Entra feature that lets frontline workers sign in once to all apps on a shared phone and sign out of all of them at shift end ([Frontline & Deskless Workers](https://www.syntaqx.com/books/workplace-and-collaboration/frontline-workers#identity-without-a-desk)).
- **Shift-based tag:** A Teams mention tag tied to the Shifts schedule that notifies only the people on shift when it's used ([Frontline & Deskless Workers](https://www.syntaqx.com/books/workplace-and-collaboration/frontline-workers#reaching-whoever-is-on-shift)).
- **Task publishing:** Publishing a task list from headquarters to many location teams, with assignment by local managers and completion reporting by location ([Frontline & Deskless Workers](https://www.syntaqx.com/books/workplace-and-collaboration/frontline-workers#publishing-tasks-to-locations)).
- **Thread:** A set of replies attached to a parent message, followed by participants and shown apart from the channel's main stream ([Channels, Threads & Direct Messages](https://www.syntaqx.com/books/workplace-and-collaboration/workplace-chat#channels-with-reply-threads)).
- **Topic:** In Zulip, a label every channel message carries that groups it into a conversation, used instead of reply threads ([Channels, Threads & Direct Messages](https://www.syntaqx.com/books/workplace-and-collaboration/workplace-chat#topics-in-zulip)).
- **Unified Grid:** Slack's 2023 to 2024 re-architecture that gave Enterprise Grid users one organization-wide view across workspaces ([Chat at Scale](https://www.syntaqx.com/books/workplace-and-collaboration/chat-architecture#unified-grid-from-workspace-to-organization)).
- **Urgent message:** A Teams message marked urgent that re-notifies the recipient every 2 minutes for 20 minutes until read ([Notifications, Presence & Attention](https://www.syntaqx.com/books/workplace-and-collaboration/notifications-and-attention#senders-signals)).
- **VAVAILABILITY:** The iCalendar component (RFC 7953) for publishing when a user can be booked, such as recurring working hours ([Email & Calendar](https://www.syntaqx.com/books/workplace-and-collaboration/email-and-calendar#free-busy-and-availability)).

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