What 인 means
As a suffix, -인 means “person.” It appears in 한국인 (“Korean person”), 직장인 (“office worker”), and 외국인 (“foreigner”); the whole word identifies the person. -인 corresponds to 人, the Chinese character for “person.”
Hangul was devised to write Korean more directly than Chinese-character writing or mixed methods such as idu, which adapted Chinese characters to represent Korean. The script was completed in 1443 and officially promulgated in 1446. Those dates describe Hangul, not the first recorded use of this syllable.
Unicode can represent 인 as one syllable or as its component Hangul letters (jamo). A compatible Korean renderer joins those letters into one visible syllable block.
Questions people ask
1Why does 인 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 인
인\C778Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.

