What 駯 means
It names a horse with a black muzzle. The gloss 馬口黑 describes one visible marking, not horses in general.
The earliest known dictionary entry is in the Yupian (玉篇), a Chinese character dictionary completed in 543 CE. Its gloss is a practical description of a horse's appearance.
Why does 駯 also have a red gloss?
The black-muzzle gloss is the safer default. The core dictionary gloss is 馬口黑 (“horse with a black muzzle”); other reference material also records 赤色 (“red”), so the historical entries are not fully uniform.
Archaic, dictionary-bound Chinese vocabulary; it does not read like a normal modern standalone word.
Do not infer the default from 朱 alone; 馬口黑 is the core gloss.
Don't confuse it with
1Questions people ask
1Why does 駯 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 駯
駯\99EFCodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.