炭
タン, すみ
charcoal, coal
JLPT2 G3 S9 F1307
屵
is
山
mountain +
厂
cliff/shape indicator → mountain cliff/crag.
炭
is
屵
# +
火
fire → fuel source dug from outcroppings → *coal* → *charcoal*; *carbon*.
[Full Kanji Etymology List]