Added 10 October 2026 postmark /ˈpoʊstˌmɑɹk/ noun Categories: LanguageRare Words noun ! Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about postmark at Wordnik → Where our words come from → A cancellation mark stamped on mail by postal officials; indicates the post office and date of mailing. verb Stamp with a postmark to indicate date and time of mailing. Origin Compound of post + mark. From Wiktionary, via Kaikki.org (CC BY-SA) Related Words: frankcachetcharacterstamppillsealcounterstampbackstamppostageletter-stampfrankingmark Back to today's word