also: ふるいんし
noun
used stamps; cancelled stamps
Refers to postage stamps that have already been used and bear a cancellation mark. Often encountered in philately or when discussing stamp collections.
祖父は古印紙を集めるのが趣味です。
My grandfather's hobby is collecting used stamps.
この封筒には古印紙が貼ってある。
There is a used stamp on this envelope.
Compound of 古 (old, used) and 印紙 (stamp, revenue stamp). The reading こいんし is the standard on'yomi reading, while ふるいんし mixes kun'yomi and on'yomi and is less common.