Where the shape comes from
A window or a face blackened by soot, smoke gathering around an opening the way it darkens the wall above a hearth — the stain of smoke giving the character its colour and its darker figurative senses of evil, secrecy, the hidden. It names darkness itself in 黑暗, and combines transparently in 黑板, a blackboard, and 黑客, a hacker, a modern coinage that simply translates black guest, someone operating in the system’s shadows.
汉字 filed under 黑
No published character on HSK Guide is filed under this radical yet. 汉字库.