皆
カイ, みな, みんな, むな
all, everything
JLPT3 G7 S9 F1267
比# line up + 白. 白 replaces an obsolete element of uncertain signification, and the reason for the selection of 白 is also obscure. *All*, *everyone* and *everything* appear to be connected with the general idea of lining up many people/objects.
[Full Kanji Etymology List]