Calendar glossary

The jargon of calendar sharing, defined in plain English. ICS, webcal, feeds, timezones, and the rest.

All-day event

An event tied to a date rather than clock times, encoded as a floating date with an exclusive end.

Assigning each calendar a color so merged views stay readable at a glance.

Copying events from a file or feed into a calendar you own and can edit, versus subscribing read-only.

A live, read-only connection from your calendar app to someone else's published calendar.

A bundle of calendars presented and shared as one merged view with a single link and feed.

The iCalendar property carrying an event's start, as either a timezone-anchored instant or a floating date.

The iCalendar field that removes specific dates from a recurring series, like a holiday skip.

How often a calendar app re-fetches a subscribed feed; the reason updates are not always instant.

The internet standard (RFC 5545) that defines how calendar data is written and exchanged.

A hosted ICS URL your calendar app checks repeatedly, so events stay current without re-importing.

The standard calendar file format (iCalendar) that every major calendar app can read.

The iCalendar pattern that expands one event definition into a repeating series.

The iCalendar revision counter that tells apps an event changed and which version wins.

An unguessable URL that grants view access to a calendar without an account.

A calendar more than one person can see, either inside one provider or across providers via a link.

When calendar events shift by an hour or a day because timezone rules were ignored or misapplied.

The stable identifier that lets calendar apps recognize an updated event as the same event.

The global reference time. Calendar systems store instants in UTC and display them in local timezones.

The iCalendar component that embeds timezone rules so event times survive daylight saving changes.

A URL scheme (webcal://) that tells a device to subscribe to a calendar feed instead of just downloading it.