Chat and Messaging Glossary · Workplace & Collaboration

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).
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).
CalDAV: The IETF protocol (RFC 4791) for accessing and managing iCalendar data over WebDAV, extended by RFC 6638 for server-side scheduling (Email & Calendar).
Canvas: A formatted document embedded in a chat channel or DM, with its own edit and comment permissions (Channels, Threads & Direct Messages).
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).
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).
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).
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).
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).
Free/busy: Time ranges and a busy status for a calendar, shared without event details, used to find meeting times (Email & Calendar).
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).
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).
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).
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).
iCalendar: The IETF data format (RFC 5545) for events, to-dos, free/busy and time zones, the interchange format for meeting invitations (Email & Calendar).
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).
iMIP: The binding (RFC 6047) that carries iTIP scheduling messages in email, with rules for authenticating organizers and attendees (Email & Calendar).
Implicit scheduling: CalDAV scheduling in which the server sends invitations, replies and cancellations when a client saves an event (Email & Calendar).
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).
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).
JSCalendar: A JSON data model for calendar data (RFC 8984), compatible with iCalendar and intended to succeed it over time (Email & Calendar).
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).
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).
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).
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).
Priority access: A Teams list of people whose messages and calls break through a user's do-not-disturb state (Notifications, Presence & Attention).
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).
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).
Resource mailbox: An Exchange mailbox for a room or piece of equipment whose calendar processing rules accept, decline or route bookings (Email & Calendar).
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).
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).
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).
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).
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).
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).
Topic: In Zulip, a label every channel message carries that groups it into a conversation, used instead of reply threads (Channels, Threads & Direct Messages).
Unified Grid: Slack's 2023 to 2024 re-architecture that gave Enterprise Grid users one organization-wide view across workspaces (Chat at Scale).
Urgent message: A Teams message marked urgent that re-notifies the recipient every 2 minutes for 20 minutes until read (Notifications, Presence & Attention).
VAVAILABILITY: The iCalendar component (RFC 7953) for publishing when a user can be booked, such as recurring working hours (Email & Calendar).

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).
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).
CalDAV: The IETF protocol (RFC 4791) for accessing and managing iCalendar data over WebDAV, extended by RFC 6638 for server-side scheduling (Email & Calendar).
Canvas: A formatted document embedded in a chat channel or DM, with its own edit and comment permissions (Channels, Threads & Direct Messages).
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).
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).
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).
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).
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).
Free/busy: Time ranges and a busy status for a calendar, shared without event details, used to find meeting times (Email & Calendar).
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).
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).
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).
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).
iCalendar: The IETF data format (RFC 5545) for events, to-dos, free/busy and time zones, the interchange format for meeting invitations (Email & Calendar).
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).
iMIP: The binding (RFC 6047) that carries iTIP scheduling messages in email, with rules for authenticating organizers and attendees (Email & Calendar).
Implicit scheduling: CalDAV scheduling in which the server sends invitations, replies and cancellations when a client saves an event (Email & Calendar).
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).
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).
JSCalendar: A JSON data model for calendar data (RFC 8984), compatible with iCalendar and intended to succeed it over time (Email & Calendar).
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).
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).
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).
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).
Priority access: A Teams list of people whose messages and calls break through a user's do-not-disturb state (Notifications, Presence & Attention).
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).
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).
Resource mailbox: An Exchange mailbox for a room or piece of equipment whose calendar processing rules accept, decline or route bookings (Email & Calendar).
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).
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).
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).
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).
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).
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).
Topic: In Zulip, a label every channel message carries that groups it into a conversation, used instead of reply threads (Channels, Threads & Direct Messages).
Unified Grid: Slack's 2023 to 2024 re-architecture that gave Enterprise Grid users one organization-wide view across workspaces (Chat at Scale).
Urgent message: A Teams message marked urgent that re-notifies the recipient every 2 minutes for 20 minutes until read (Notifications, Presence & Attention).
VAVAILABILITY: The iCalendar component (RFC 7953) for publishing when a user can be booked, such as recurring working hours (Email & Calendar).