A calendar, which may feature a single date, or a month-view calendar. Not to be confused with the Tear-Off Calendar.
The date displays July 17 on some versions on this emoji. This is the date that iCal for Mac was first announced at MacWorld Expo in 2002 and now also World Emoji Day.
Twitter previously showed July 15 — Twitter’s launch date — but changed this to March 21 in Twemoji 2.0. This is Twitter's founding date. The reason stated was to avoid confusion being so close to July 17, but not the same.
Calendar was approved as part of Unicode 6.0 in 2010 and added to Emoji 1.0 in 2015.
📅 July 17
📅 World Emoji Day