What 乆 means
It means “a long time”; 乆 is a variant of standard 久. Its written form arose through a stroke error.
Han-dynasty bamboo slips preserve 久; late Warring States and Qin writings already use it for “long time.” The early Chinese dictionary Shuowen Jiezi links 久 to moxibustion, a heat treatment with mugwort, but this origin remains uncertain. Later formulas use 久仰 for formal respect and 天长地久 for lasting attachment.
Nonstandard and archaizing; 乆 can read as a writing error.
Use 久 in ordinary Chinese; 乆 can look like a mistake.
Questions people ask
1Why does 乆 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 乆
乆\4E46Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.