燧
スイ, ひうち, ひきり, のろし
signal fire
JLPT0 G13 S0 F5000
Abbreviated form# of 邃 (follow a hole or underground passage) + 火 fire → *signal fire* sent from or observed by a tower reached via an underground passage (compare 隧) → *make a fire*; *make a fire with flint and steel*.
[Full Kanji Etymology List]