A white X inside a green square. It means no, close, or cancel, much like ❌.
People use ❎ to dismiss something or mark an option they reject. The green color confuses many readers, since green usually means yes, so ❌ is the clearer choice for a firm no.
Facts
Cross mark button ❎ is an emoji in the symbols category, under other symbol. It is one of the early emoji from Japanese phones, standardized in Unicode 6.0 (2010). On GitHub, Slack and other apps you can type it as :negative_squared_cross_mark: or :cross_mark_button:. People also look for it with words like “button”, “cross”, “mark”, or “multiplication”.
Timeline
2010Added to the emoji standard (Unicode 6.0)
Design history
Google (Noto)
2015
2017
2019
2021
Twemoji (X, Discord)
2014
Google Noto Emoji images: Apache 2.0. Twemoji graphics by X Corp and contributors: CC-BY 4.0.