Keyboard key with rounded corners and the number 4 in the middle. Four cardinal directions, four seasons. Stands for luck in the western world (shamrock) and is an unlucky number in Asia.
The keycap: 4 emoji was introduced in 2010 and released as part of the Unicode 11.0 standard. This emoji can be found under the symbols
category. Because the keycap: 4 emoji has been around for quite some time, it should display correctly in the majority of operating systems.