Definition from Wiktionary, the free dictionary
- to cover up a trans person's identified gender or the role they have played in an event
2013 February 18, Cristan, “Interview With an Actual Stonewall Riot Veteran: The Ciswashing of Stonewall Must End!”:
- Numerous media outlets recounted how the noble gays and lesbians fought that night – never mentioning trans folk… carrying on that long and painful tradition of ciswashing queer history - especially Stonewall history.
2013 September 10, Reubs Walsh, “Same-sex marriage, ciswash and a call to continued solidarity”: