Editing Postmark (section)

== Similar marks ==
[[File:FAM 18 Round the World 1939 (front).jpg|thumb|1939 Around the World flight with red flight cachet]]
A postmark should not be confused with the [[Cancellation (mail)|killer]] which are lines, bars, etc. used to cancel a postage stamp. The killer acts as the [[Cancellation (mail)|cancellation]], though the postmark can also serve this purpose. Neither should a postmark be confused with [[overprint]]s generally, or [[pre-cancels]] (stamps that have been cancelled before the [[envelope]] or package to which they are affixed is submitted or deposited for acceptance into the [[mailstream]], they most commonly have taken the form of a pre-printed city name on the stamp) specifically, which generally do not indicate a date.

Flight [[cachet]]s, more or less elaborate rubber-stamps on an envelope indicating on which flight (typically a [[first flight]]), a [[first flight cover]] has traveled via [[airmail]], are in addition to the postmark and are not postmarks either.<ref>{{cite journal |title=Collecting those strange Tongan stamps&nbsp;— on cover |journal=Scott Stamp Monthly |date=August 2002}}</ref>