title: Difference between Occurrence and Instance in iCalendar standard?
body: <p>Are there any difference between terms &quot;occurrence&quot; and &quot;instance&quot; in iCalendar <a href="https://www.rfc-editor.org/rfc/rfc5545" rel="nofollow noreferrer">RFC 5545</a>?</p>
  <p>I found that CalDAV <a href="https://www.rfc-editor.org/rfc/rfc4791" rel="nofollow noreferrer">RFC 4791</a> is using term &quot;instance&quot; only, there is no term &quot;occurrence&quot; used in it.</p>
  <p>It looks like these are synonyms or am I wrong?</p>