noun, noun which may take the genitive case particle 'no'
ember; brand; stub (of used candle, match, etc.)
Refers to the remains of something that has been burning: a glowing ember, a charred piece of wood, or the stub of a candle or match after use.
We put out the embers of the campfire with water.
There were many match stubs in the ashtray.
残り火 specifically means remaining fire or live embers, often with a poetic nuance, whereas 燃えさし is a more concrete term for the physical leftover piece.
Standard kanji-kana mixed spelling; the most common written form.
Alternate kanji spelling using 差し; less common but still encountered.
Rare variant using 止し; may be seen in older texts.
Compound of 燃え (moe, the continuative form of 燃える 'to burn') + さし (sashi, from 差す 'to insert' or 'to remain', here indicating a leftover state). The spelling 燃えさし is the most common representation.