What 사 means
Read the whole Korean word. Separate Korean words written 사 include the numeral “four” and the noun “death”; in longer words, 사 may be part of a verb form or suffix. If someone sends it alone, ask which word they mean before interpreting it.
How did Hangul develop?
King Sejong commissioned Hangul so people could write Korean without mastering Chinese characters. The earliest surviving notice of its creation dates to 1443; the guide Hunminjeongeum, which explained the new writing system, was published in 1446.
Earlier methods—Idu, Hyangchal, and Gugyeol—used Chinese characters to represent Korean. They are historical writing traditions, not earlier shapes of 사. Hangul later coexisted with Chinese-character writing; by the 1990s, major South Korean newspapers had largely stopped using those characters.
How do I type 사?
With Korean input active, enter ㅅ then ㅏ. The input method combines the consonant and vowel into 사.
Unicode also allows 사 to be represented as a precomposed syllable or an equivalent sequence of conjoining Hangul letters, called Jamo. They can display alike despite having different encoded sequences; the font controls the components’ exact placement.
사 is ordinary Korean text; an isolated block carries no reliable emotional message.
Do not read “death” into a lone 사; ask for the full Korean word.
Questions people ask
1Why does 사 show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
How to type 사
사\C0ACCodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.

